ORCID Profile
0000-0002-8452-1350
Current Organisation
Griffith University - Gold Coast Campus
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In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Characterisation of Biological Macromolecules | Analytical Biochemistry | Analytical Chemistry | Biochemistry and Cell Biology | Optical Properties of Materials | Medicinal and Biomolecular Chemistry | Biomaterials | Analytical Spectrometry | Biologically Active Molecules | Nanochemistry and Supramolecular Chemistry | Proteins and Peptides | Nanophotonics | Optical Physics not elsewhere classified | Medical Biotechnology | Nanotechnology | Regenerative Medicine (incl. Stem Cells and Tissue Engineering) | Nanobiotechnology | Cell Development, Proliferation and Death |
Expanding Knowledge in the Biological Sciences | Expanding Knowledge in the Chemical Sciences | Crop Protection Chemicals | Expanding Knowledge in Technology | Health Related to Ageing | Expanding Knowledge in the Physical Sciences | Expanding Knowledge in Engineering | Scientific Instruments | Infectious Diseases
Publisher: American Chemical Society (ACS)
Date: 19-01-2010
DOI: 10.1021/PR900956X
Abstract: With the emergence of glycoproteomics, there is a need to develop bioinformatic tools to identify glycopeptides in protease digests of glycoproteins. GlycoSpectrumScan is a web-based tool that identifies the glycoheterogeneity on a peptide from mass spectrometric data. Two experimental data sets are required as inputs: (1) oligosaccharide compositions of the N- and/or O-linked glycans present in the s le and (2) in silico derived peptide masses of proteolytically digested proteins with a potential number of N- and/or O-glycosylation sites. GlycoSpectrumScan uses MS data, rather than MS/MS data, to identify glycopeptides and determine the relative distribution of N- and O-glycoforms at each site. It is functional for assigning monosaccharide compositions on glycopeptides with single and multiple sites of glycosylation. The algorithm allows the input of raw mass data, including multiply charged ions, making it applicable for both ESI and MALDI data from all mass spectrometer platforms. Manual analysis time for identifying glycosylation heterogeneity at each site on glycoprotein(s) is substantially decreased. The application of this tool to characterize the N- and O-linked glycopeptides from human secretory IgA (sIgA), consisting of secretory component (7 N-linked sites), IgA1 (2 N-linked, <or=5 O-linked sites), IgA2 (4 N-linked sites) and J-chain (1 N-linked site) is described. GlycoSpectrumScan is freely available at www.glycospectrumscan.org .
Publisher: Cold Spring Harbor Laboratory
Date: 05-04-2019
DOI: 10.1101/597922
Abstract: The CaptiveSpray source ensures a stable spray and excellent nano ESI performance facilitated by a vortex gas that sweeps around the emitter spray tip to support liquid desolvation and focus the Taylor cone. Enriching the vortex gas with dopant solvents provides tremendous opportunities to increase ionization efficiency, in particular for hydrophilic compounds such as glycopeptides. How this CaptiveSpray nanobooster benefits their analysis, however, has to date not been systematically studied. We evaluated various dopant solvents such as (i) acetone (ii) acetonitrile (iii) methanol (iv) ethanol and (v) isopropanol for their ability to enhance glycopeptide ionization. Using a synthetic IgG2 glycopeptide as a standard, acetonitrile provided a five-fold increase in signal intensities and resulted in an overall charge state increase compared to conventional CaptiveSpray ionization. This trend remained the same when tryptic IgG (glyco)peptides were analyzed and allowed highly sensitive detection of glycopeptides even without any enrichment. While acetone dopant gas enhanced glycopeptide ionization by doubling glycopeptide signal intensities, all other tested solvents resulted either in ion suppression or adduct formation. This is in agreement with and can be explained by their in idual physio-chemical properties of the solvents. Finally, by omitting glycopeptide enrichment steps, we established a bias-free human Immunoglobulin G (IgG) subclass specific glycosylation profile applying the optimized CaptiveSpray nanoBooster nano-LC-ESI-MS/MS analysis conditions.
Publisher: Springer Science and Business Media LLC
Date: 11-2021
DOI: 10.1038/S41592-021-01309-X
Abstract: Glycoproteomics is a powerful yet analytically challenging research tool. Software packages aiding the interpretation of complex glycopeptide tandem mass spectra have appeared, but their relative performance remains untested. Conducted through the HUPO Human Glycoproteomics Initiative, this community study, comprising both developers and users of glycoproteomics software, evaluates solutions for system-wide glycopeptide analysis. The same mass spectrometry based glycoproteomics datasets from human serum were shared with participants and the relative team performance for N- and O -glycopeptide data analysis was comprehensively established by orthogonal performance tests. Although the results were variable, several high-performance glycoproteomics informatics strategies were identified. Deep analysis of the data revealed key performance-associated search parameters and led to recommendations for improved ‘high-coverage’ and ‘high-accuracy’ glycoproteomics search solutions. This study concludes that erse software packages for comprehensive glycopeptide data analysis exist, points to several high-performance search strategies and specifies key variables that will guide future software developments and assist informatics decision-making in glycoproteomics.
Publisher: Cold Spring Harbor Laboratory
Date: 27-08-2018
DOI: 10.1101/401141
Abstract: Glycomics targets released glycans from proteins, lipids and proteoglycans. High throughput glycomics is based on mass spectrometry (MS) that increasingly depends on exchange of data with databases and the use of software. This requires an agreed format for accurately recording of experiments, developing consistent storage modules and granting public access to glycomic MS data. The introduction of the MIRAGE (Mimimum Requirement for A Glycomics Experiment) reporting standards for glycomics was the first step towards automating glycomic data recording. This report describes a glycomic e-infrastructure utilizing a well established glycomics recording format (GlycoWorkbench), and a dedicated web tool for submitting MIRAGE-compatible MS information into a public experimental repository, UniCarb-DR. The submission of data to UniCarb-DR should be a part of the submission process for publications with glycomics MS n that conform to the MIRAGE guidelines. The structure of this pipeline allows submission of most MS workflows used in glycomics.
Publisher: Elsevier BV
Date: 04-2018
Publisher: Wiley
Date: 15-12-2010
DOI: 10.1111/J.1742-4658.2009.07429.X
Abstract: The O-glycosylation of Ser and Thr by N-acetylgalactosamine-linked (mucin-type) oligosaccharides is often overlooked in protein analysis. Three characteristics make O-linked glycosylation more difficult to analyse than N-linked glycosylation, namely: (a) no amino acid consensus sequence is known (b) there is no universal enzyme for the release of O-glycans from the protein backbone and (c) the density and number of occupied sites may be very high. For significant biological conclusions to be drawn, the complete picture of O-linked glycosylation on a protein needs to be determined. This review specifically addresses the analytical approaches that have been used, and the challenges remaining, in the characterization of both the composition and structure of mucin-type O-glycans, and the determination of the occupancy and heterogeneity at each amino acid attachment site.
Publisher: American Chemical Society (ACS)
Date: 04-01-2016
Publisher: Portland Press Ltd.
Date: 24-05-2005
DOI: 10.1042/BJ20042091
Abstract: XylT (β1,2-xylosyltransferase) is a unique Golgi-bound glycosyltransferase that is involved in the biosynthesis of glycoprotein-bound N-glycans in plants. To delineate the catalytic domain of XylT, a series of N-terminal deletion mutants was heterologously expressed in insect cells. Whereas the first 54 residues could be deleted without affecting the catalytic activity of the enzyme, removal of an additional five amino acids led to the formation of an inactive protein. Characterization of the N-glycosylation status of recombinant XylT revealed that all three potential N-glycosylation sites of the protein are occupied by N-linked oligosaccharides. However, an unglycosylated version of the enzyme displayed substantial catalytic activity, demonstrating that N-glycosylation is not essential for proper folding of XylT. In contrast with most other glycosyltransferases, XylT is enzymatically active in the absence of added metal ions. This feature is not due to any metal ion directly associated with the enzyme. The precise acceptor substrate specificity of XylT was assessed with several physiologically relevant compounds and the xylosylated reaction products were subsequently tested as substrates of other Golgi-resident glycosyltransferases. These experiments revealed that the substrate specificity of XylT permits the enzyme to act at multiple stages of the plant N-glycosylation pathway.
Publisher: Oxford University Press (OUP)
Date: 07-11-2011
Publisher: Elsevier BV
Date: 12-2020
Publisher: Springer Science and Business Media LLC
Date: 07-2004
DOI: 10.1007/S11103-004-1558-3
Abstract: The recent draft sequencing of the rice (Oryza sativa) genome has enabled a genetic analysis of the glycosylation capabilities of an agroeconomically important group of plants, the monocotyledons. In this study, we have not only identified genes putatively encoding enzymes involved in N-glycosylation, but have examined by MALDI-TOF MS the structures of the N-glycans of rice and other monocotyledons (maize, wheat and dates Zea mays, Triticum aestivum and Phoenix dactylifera) these data show that within the plant kingdom the types of N-glycans found are very similar between monocotyledons, dicotyledons and gymnosperms. Subsequently, we constructed expression vectors for the key enzymes forming plant-typical structures in rice, N-acetylglucosaminyltransferase I (GlcNAc-TI EC 2.4.1.101), core alpha1,3-fucosyltransferase (FucTA EC 2.4.1.214) and beta1,2-xylosyltransferase (EC 2.4.2.38) and successfully expressed them in Pichia pastoris. Rice GlcNAc-TI, FucTA and xylosyltransferase are therefore the first monocotyledon glycosyltransferases involved in N-glycan biosynthesis to be characterised in a recombinant form.
Publisher: Elsevier BV
Date: 2014
DOI: 10.1016/J.BBAPAP.2013.04.018
Abstract: The UniCarb-DB database is an emerging public glycomics data repository, containing over 500 tandem mass spectra (as of March 2013) of glycans released from glycoproteins. A major challenge in glycomics research is to provide and maintain high-quality datasets that will offer the necessary ersity to support the development of accurate bioinformatics tools for data deposition and analysis. The role of UniCarb-DB, as an archival database, is to provide the glycomics community with open-access to a comprehensive LC MS/MS library of N- and O- linked glycans released from glycoproteins that have been annotated with glycosidic and cross-ring fragmentation ions, retention times, and associated experimental metadata descriptions. Here, we introduce the UniCarb-DB data submission pipeline and its practical application to construct a library of LC-MS/MS glycan standards that forms part of this database. In this context, an independent consortium of three laboratories was established to analyze the same 23 commercially available oligosaccharide standards, all by using graphitized carbon-liquid chromatography (LC) electrospray ionization (ESI) ion trap mass spectrometry in the negative ion mode. A dot product score was calculated for each spectrum in the three sets of data as a measure of the comparability that is necessary for use of such a collection in library-based spectral matching and glycan structural identification. The effects of charge state, de-isotoping and threshold levels on the quality of the input data are shown. The provision of well-characterized oligosaccharide fragmentation data provides the opportunity to identify determinants of specific glycan structures, and will contribute to the confidence level of algorithms that assign glycan structures to experimental MS/MS spectra. This article is part of a Special Issue entitled: Computational Proteomics in the Post-Identification Era. Guest Editors: Martin Eisenacher and Christian Stephan.
Publisher: MDPI AG
Date: 15-12-2017
Publisher: Elsevier BV
Date: 08-2016
DOI: 10.1016/J.BBAGEN.2016.03.012
Abstract: Complex diseases such as cancer are a consequence of numerous causes. State of the art personalised medicine approaches are mostly based on evaluating patients' in idual genetic background. Despite the advances of genomics it fails to take in idual dynamic influences into account that contribute to the in idual and unique glycomic and glycoproteomic "configurations" of every living being. Glycomic and glycoproteomic-based personalised medicine diagnostics are still in their infancies, however some initial success stories indicate that these fields are highly promising to mediate novel early diagnosis and disease stratification markers, subsequently resulting in improved patient well-being and reduced treatment costs. In this review we not only summarise current protein glycosylation based ex les that substantially improve or possess great potential for personalised medicine, but also describe current limitations as well as future perspectives and challenges associated with establishing protein glycosylation aspects for this purpose. Many protein biomarkers currently in clinical use are glycoproteins, however, their glycosylation status is seldom evaluated in a clinical context. To date just few ex les have already been successfully translated into clinical practice, making protein glycosylation a highly promising diagnostic target with humongous potential for personalised medicine. There is an urgent need for markers that enable the establishment of an in idualised and optimised patient treatment at the earliest disease stage possible. The glycosylation status of a patient and/or specific marker proteins can provide important clues that result in improved patient management. This article is part of a Special Issue entitled "Glycans in personalised medicine" Guest Editor: Professor Gordan Lauc.
Publisher: Wiley
Date: 04-2009
DOI: 10.1111/J.1365-2958.2009.06675.X
Abstract: Infections with the microaerophilic parasite Trichomonas vaginalis are treated with the 5-nitroimidazole drug metronidazole, which is also in use against Entamoeba histolytica, Giardia intestinalis and microaerophilic/anaerobic bacteria. Here we report that in T. vaginalis the flavin enzyme thioredoxin reductase displays nitroreductase activity with nitroimidazoles, including metronidazole, and with the nitrofuran drug furazolidone. Reactive metabolites of metronidazole and other nitroimidazoles form covalent adducts with several proteins that are known or assumed to be associated with thioredoxin-mediated redox regulation, including thioredoxin reductase itself, ribonucleotide reductase, thioredoxin peroxidase and cytosolic malate dehydrogenase. Disulphide reducing activity of thioredoxin reductase was greatly diminished in extracts of metronidazole-treated cells and intracellular non-protein thiol levels were sharply decreased. We generated a highly metronidazole-resistant cell line that displayed only minimal thioredoxin reductase activity, not due to diminished expression of the enzyme but due to the lack of its FAD cofactor. Reduction of free flavins, readily observed in metronidazole-susceptible cells, was also absent in the resistant cells. On the other hand, iron-depleted T. vaginalis cells, expressing only minimal amounts of PFOR and hydrogenosomal malate dehydrogenase, remained fully susceptible to metronidazole. Thus, taken together, our data suggest a flavin-based mechanism of metronidazole activation and thereby challenge the current model of hydrogenosomal activation of nitroimidazole drugs.
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D0MO00044B
Abstract: Glycomics and sialiomics of isolated synaptosomes reveal distinct glycosylation of surface proteins localized in the active zone of synapses.
Publisher: Oxford University Press (OUP)
Date: 20-03-2014
Publisher: Elsevier BV
Date: 08-2005
Publisher: Springer Science and Business Media LLC
Date: 18-09-2012
DOI: 10.1038/NCOMMS2070
Abstract: Lysosomal storage diseases are a class of over 70 rare genetic diseases that are amenable to enzyme replacement therapy. Towards developing a plant-based enzyme replacement therapeutic for the lysosomal storage disease mucopolysaccharidosis I, here we expressed α-L-iduronidase in the endosperm of maize seeds by a previously uncharacterized mRNA-targeting-based mechanism. Immunolocalization, cellular fractionation and in situ RT-PCR demonstrate that the α-L-iduronidase protein and mRNA are targeted to endoplasmic reticulum (ER)-derived protein bodies and to protein body-ER regions, respectively, using regulatory (5'- and 3'-UTR) and signal-peptide coding sequences from the γ-zein gene. The maize α-L-iduronidase exhibits high activity, contains high-mannose N-glycans and is amenable to in vitro phosphorylation. This mRNA-based strategy is of widespread importance as plant N-glycan maturation is controlled and the therapeutic protein is generated in a native form. For our target enzyme, the N-glycan structures are appropriate for downstream processing, a prerequisite for its potential as a therapeutic protein.
Publisher: Frontiers Media SA
Date: 16-03-2022
Abstract: Normal early human B-cell development from lymphoid progenitors in the bone marrow depends on instructions from elements in that microenvironment that include stromal cells and factors secreted by these cells including the extracellular matrix. Glycosylation is thought to play a key role in such interactions. The sialyltransferase ST6Gal1, with high expression in specific hematopoietic cell types, is the only enzyme thought to catalyze the terminal addition of sialic acids in an α2-6-linkage to galactose on N-glycans in such cells. Expression of ST6Gal1 increases as B cells undergo normal B-lineage differentiation. B-cell precursor acute lymphoblastic leukemias (BCP-ALLs) with differentiation arrest at various stages of early B-cell development have widely different expression levels of ST6GAL1 at diagnosis, with high ST6Gal1 in some but not in other relapses. We analyzed the consequences of increasing ST6Gal1 expression in a diagnosis s le using lentiviral transduction. NSG mice transplanted with these BCP-ALL cells were monitored for survival. Compared to mice transplanted with leukemia cells expressing original ST6Gal1 levels, increased ST6Gal1 expression was associated with significantly reduced survival. A cohort of mice was also treated for 7 weeks with vincristine chemotherapy to induce remission and then allowed to relapse. Upon vincristine discontinuation, relapse was detected in both groups, but mice transplanted with ST6Gal1 overexpressing BCP-ALL cells had an increased leukemia burden and shorter survival than controls. The BCP-ALL cells with higher ST6Gal1 were more resistant to long-term vincristine treatment in an ex vivo tissue co-culture model with OP9 bone marrow stromal cells. Gene expression analysis using RNA-seq showed a surprisingly large number of genes with significantly differential expression, of which approximately 60% increased mRNAs, in the ST6Gal1 overexpressing BCP-ALL cells. Pathways significantly downregulated included those involved in immune cell migration. However, ST6Gal1 knockdown cells also showed increased insensitivity to chemotherapy. Our combined results point to a context-dependent effect of ST6Gal1 expression on BCP-ALL cells, which is discussed within the framework of its activity as an enzyme with many N-linked glycoprotein substrates.
Publisher: Elsevier BV
Date: 04-2013
Publisher: Oxford University Press (OUP)
Date: 24-07-2012
Abstract: Mucosal epithelial surfaces, such as line the oral cavity, are common sites of microbial colonization by bacteria, yeast and fungi. The microbial interactions involve adherence between the glycans on the host cells and the carbohydrate-binding proteins of the pathogen. Saliva constantly bathes the buccal cells of the epithelial surface of the mouth and we postulate that the sugars on the salivary glycoproteins provide an innate host immune mechanism against infection by competitively inhibiting pathogen binding to the cell membranes. The structures of the N- and O-linked oligosaccharides on the glycoproteins of saliva and buccal cell membranes were analyzed using capillary carbon liquid chromatography-electrospray ionization MS/MS. The 190 glycan structures that were characterized were qualitatively similar, but differed quantitatively, between saliva and epithelial buccal cell membrane proteins. The similar relative abundance of the terminal glycan epitope structures (e.g. ABO(H) blood group, sialylation and Lewis-type antigens) on saliva and buccal cell membrane glycoproteins indicated that the terminal N- and O-linked glycan substructures in saliva could be acting as decoy-binding receptors to competitively inhibit the attachment of pathogens to the surface of the oral mucosa. A flow cytometry-based binding assay quantified the interaction between buccal cells and the commensal oral pathogen Candida albicans. Whole saliva and released glycans from salivary proteins inhibited the interaction of C. albicans with buccal epithelial cells, confirming the protective role of the glycans on salivary glycoproteins against pathogen infection.
Publisher: Elsevier BV
Date: 2019
Publisher: Elsevier BV
Date: 05-2006
DOI: 10.1016/J.PHYTOCHEM.2006.01.021
Abstract: Our work with almond peptide N-glycosidase A made us interested also in the alpha1,3/4-fucosidase which is used as a specific reagent for glycoconjugate analysis. The enzyme was purified to presumed homogeneity by a series of chromatographic steps including dye affinity and fast-performance anion exchange chromatography. The 63 kDa band was analyzed by tandem mass spectrometry which yielded several partial sequences. A homology search retrieved the hypothetical protein Q8GW72 from Arabidopsis thaliana. This protein has recently been described as being specific for alpha1,2-linkages. However, cDNA cloning and expression in Pichia pastoris of the A. thaliana fucosidase showed that it hydrolyzed fucose in 3- and 4-linkage to GlcNAc in Lewis determinants whereas neither 2-linked fucose nor fucose in 3-linkage to the innermost GlcNAc residue were attacked. This first cloning of a plant alpha1,3/4-fucosidase also confirmed the identity of the purified almond enzyme and thus settles the notorious uncertainty about its molecular mass. The alpha1,3/4-fucosidase from Arabidopsis exhibited striking sequence similarity with an enzyme of similar substrate specificity from Streptomyces sp. (Q9Z4I9) and with putative proteins from rice.
Publisher: Elsevier BV
Date: 06-2003
DOI: 10.1016/S0022-2836(03)00403-0
Abstract: Mal d 2 is a thaumatin-like protein and important allergen of apple fruits that is associated with IgE-mediated symptoms in apple allergic in iduals. We obtained a full-length cDNA clone of Mal d 2 from RNA isolated from ripe apple (Malus domestica cv. Golden Delicious). The cDNA's open reading frame encodes a protein of 246 amino acid residues including a signal peptide of 24 residues and two putative glycosylation sites. The deduced amino acid sequence of the mature Mal d 2 protein results in a predicted molecular mass of 23,210.9Da and a calculated pI of 4.55. Sequence comparisons and molecular modeling place Mal d 2 among those pathogenesis-related thaumatin-like proteins that contain a conserved acidic cleft. In order to ensure the correct formation of the protein's eight conserved disulfide bridges we expressed Mal d 2 in Nicotiana benthamiana plants by the use of a tobacco mosaic viral vector. Transfected N.benthamiana plants accumulated Mal d 2 to levels of at least 2% of total soluble protein. MALDI-TOF mass spectrometric analyses of the recombinant Mal d 2 and its proteolytic fragments showed that the apple-specific leader peptide was correctly cleaved off by the host plant and that the mature recombinant protein was intact and not glycosylated. Purified recombinant Mal d 2 displayed the ability to bind IgE from apple-allergic in iduals equivalent to natural Mal d 2. In addition, the recombinant thaumatin-like Mal d 2 exhibited antifungal activity against Fusarium oxysporum and Penicillium expansum, implying a function in plant defense against fungal pathogens.
Publisher: Elsevier BV
Date: 2021
DOI: 10.1016/J.IJPARA.2021.06.004
Abstract: Infections by blood flukes (Cardicola spp.) are considered the most significant health issue for ranched bluefin tuna, a major aquaculture industry in Japan and Australia. The host-parasite interfaces of trematodes, namely their teguments, are particularly rich in carbohydrates, which function both in evasion and modulation of the host immune system, while some are primary antigenic targets. In this study, histochemistry and mass spectrometry techniques were used to profile the glycans of Cardicola forsteri. Fluorescent lectin staining of adult flukes indicates the presence of oligomannose (Concanavalin A-reactive) and fucosylated (Pisum sativum agglutinin-reactive) N-glycans. Additionally, reactivity of succinylated wheat germ agglutinin (s-WGA) was localised to several internal organs of the digestive and monoecious reproductive systems. Glycan structures were further investigated with tandem mass spectrometry, which revealed structures indicated by lectin reactivity. While O-glycans from these adult specimens were not detectable by mass spectrometry, several oligomannose, paucimannosidic, and complex-type N-glycans were identified, including some carrying hexuronic acid and many carrying core xylose. This is, to our knowledge, the first glycomic characterisation of a marine platyhelminth, with broader implications for research into other trematodes.
Publisher: Wiley
Date: 19-09-2011
Abstract: Despite the success of several international initiatives the glycosciences still lack a managed infrastructure that contributes to the advancement of research through the provision of comprehensive structural and experimental glycan data collections. UniCarbKB is an initiative that aims to promote the creation of an online information storage and search platform for glycomics and glycobiology research. The knowledgebase will offer a freely accessible and information-rich resource supported by querying interfaces, annotation technologies and the adoption of common standards to integrate structural, experimental and functional data. The UniCarbKB framework endeavors to support the growth of glycobioinformatics and the dissemination of knowledge through the provision of an open and unified portal to encourage the sharing of data. In order to achieve this, the framework is committed to the development of tools and procedures that support data annotation, and expanding interoperability through cross-referencing of existing databases. Database URL: www.unicarbkb.org.
Publisher: Wiley
Date: 03-2004
DOI: 10.1111/J.1365-2222.2004.01897.X
Abstract: IgE antibodies against carbohydrate epitopes have been identified recently as a major cause of in vitro double positivity to honeybee (HB) and vespid venom in patients with stinging-insect allergy. As these antibodies possibly have low clinical relevance they may be misleading in the diagnosis of venom allergy. To confirm the role of carbohydrate epitopes in double positivity and to locate the responsible glycoallergens in HB and yellow jacket (YJ) venom by western blot. Immunoblot inhibition using HB venom, YJ venom and two glycoprotein sources displaying 1-3-fucosylated N-glycans (i.e. oilseed rape (OSR) pollen, and the synthetic neo-glycoprotein fucosylated/xylosylated N-glycans from bromelain coupled to bovine serum albumin (MUXF-BSA)) as inhibitors were performed with sera from 15 double-positive patients with stinging-insect allergy. Additionally, reactivity with blotted hymenoptera venoms of a carbohydrate-specific rabbit antiserum against OSR pollen was investigated. Major venom glycoallergens binding with carbohydrate-specific human IgE and rabbit IgG were detected in HB venom at 42 (hyaluronidase (HYA)), 46, 65 and 95 kDa, and in YJ venom at 38 and 43 kDa (HYA). Antibody binding to these allergens was completely lost after periodate treatment. Glycans of HB phospholipase were bound by patients' IgE only after protein denaturation. In 10 of the 15 patients the reactivity was with the second venom because of carbohydrates alone. The high-molecular-weight glycoallergens identified in HB venom probably correspond to similar proteins described earlier, including allergens B and C. The 38-kDa YJ allergen might represent a homologue of V mac 3. The data confirm the proposed role of carbohydrate-specific IgE in double positivity to HB and YJ venom and shed new light on some previously described minor hymenoptera allergens of uncertain clinical significance. The consideration of carbohydrate-specific IgE may allow to discriminate between patients with potentially relevant and patients with non-relevant double sensitization.
Publisher: Elsevier BV
Date: 05-2006
DOI: 10.1016/J.BMC.2005.12.051
Abstract: In order to develop spin traps with an optimal ratio between hydrophilic and lipophilic properties, low toxicity, and high stability of spin adducts (especially with superoxide radicals), several EMPO-derived spin traps have recently been synthesized forming more stable superoxide adducts (t(1/2) > 20 min) than DMPO or DEPMPO. In this study, ESR-, 1H-, and 13C-NMR data of several phenyl- or n-pentyl-substituted EMPO derivatives are presented with full signal assignment. Methyl groups at position 3 or 4 stabilized the superoxide adducts considerably. Spin adducts from other oxygen- and carbon-centered radicals (e.g., derived from methanol or linoleic acid hydroperoxide) are also described.
Publisher: Springer Science and Business Media LLC
Date: 25-11-2016
DOI: 10.1038/NCOMMS13507
Abstract: Epigenetic alterations may provide important insights into gene-environment interaction in inflammatory bowel disease (IBD). Here we observe epigenome-wide DNA methylation differences in 240 newly-diagnosed IBD cases and 190 controls. These include 439 differentially methylated positions (DMPs) and 5 differentially methylated regions (DMRs), which we study in detail using whole genome bisulphite sequencing. We replicate the top DMP ( RPS6KA2 ) and DMRs ( VMP1, ITGB2 and TXK ) in an independent cohort. Using paired genetic and epigenetic data, we delineate methylation quantitative trait loci VMP1/microRNA-21 methylation associates with two polymorphisms in linkage disequilibrium with a known IBD susceptibility variant. Separated cell data shows that IBD-associated hypermethylation within the TXK promoter region negatively correlates with gene expression in whole-blood and CD8 + T cells, but not other cell types. Thus, site-specific DNA methylation changes in IBD relate to underlying genotype and associate with cell-specific alteration in gene expression.
Publisher: American Association for Cancer Research (AACR)
Date: 14-01-2016
DOI: 10.1158/0008-5472.CAN-15-1232
Abstract: Antibodies of IgA isotype effectively engage myeloid effector cells for cancer immunotherapy. Here, we describe preclinical studies with an Fc engineered IgA2m(1) antibody containing the variable regions of the EGFR antibody cetuximab. Compared with wild-type IgA2m(1), the engineered molecule lacked two N-glycosylation sites (N166 and N337), two free cysteines (C311 and C472), and contained a stabilized heavy and light chain linkage (P221R mutation). This novel molecule displayed improved production rates and biochemical properties compared with wild-type IgA. In vitro, Fab- and Fc-mediated effector functions, such as inhibition of ligand binding, receptor modulation, and engagement of myeloid effector cells for antibody-dependent cell-mediated cytotoxicity, were similar between wild-type and engineered IgA2. The engineered antibody displayed lower levels of terminal galactosylation leading to reduced asialoglycoprotein-receptor binding and to improved pharmacokinetic properties. In a long-term in vivo model against EGFR-positive cancer cells, improved serum half-life translated into higher efficacy of the engineered molecule, which required myeloid cells expressing human FcαRI for its full efficacy. However, Fab-mediated effector functions contributed to the in vivo efficacy because the novel IgA antibody demonstrated therapeutic activity also in non-FcαRI transgenic mice. Together, these results demonstrate that engineering of an IgA antibody can significantly improve its pharmacokinetics and its therapeutic efficacy to inhibit tumor growth in vivo. Cancer Res 76(2) 403–17. ©2015 AACR.
Publisher: Springer Science and Business Media LLC
Date: 10-06-2014
Abstract: A number of genetic and immunological studies give impetus for investigating the role of glycosylation in IBD. Experimental mouse models have helped to delineate the role of glycosylation in intestinal mucins and to explore the putative pathogenic role of glycosylation in colitis. These experiments have been extended to human studies investigating the glycosylation patterns of intestinal mucins as well as levels of glycans of serum glycoproteins and expression of glycan receptors. These early human studies have generated interesting hypotheses regarding the pathogenic role of glycans in IBD, but have generally been restricted to fairly small underpowered studies. Decreased glycosylation has been observed in the intestinal mucus of patients with IBD, suggesting that a defective inner mucus layer might lead to increased bacterial contact with the epithelium, potentially triggering inflammation. In sera, decreased galactosylation of IgG has been suggested as a diagnostic marker for IBD. Advances in glycoprofiling technology make it technically feasible and affordable to perform high-throughput glycan pattern analyses and to build on previous work investigating a much wider range of glycan parameters in large numbers of patients.
Publisher: Elsevier BV
Date: 04-2018
Publisher: MDPI AG
Date: 06-01-2011
DOI: 10.3390/RS3010042
Publisher: Cold Spring Harbor Laboratory
Date: 04-08-2021
DOI: 10.1101/2021.08.04.451140
Abstract: Porous Graphitized Carbon nano-liquid chromatography tandem mass spectrometry (PGC-nLC-MS/MS) is a glycomics technique with the unique capacity to differentiate isobaric glycans. The lack of suitable software tools integrating chromatography and MS-information delivered by PGC-nLC-MS/MS has been limiting fast and robust glycan identification and quantitation. We report a LC-system-independent strategy called GlycoRRT that combines relative retention time (RRT) and negative ion fragment spectra analyses for isobaric structure-specific glycomics of PGC-nLC-MS/MS data. The GlycoRRT toolset is fully customizable and easily adaptable enabling semi-automated high-throughput structural assignments. The current library contains over 200 entries and their in idual meta-data (MS instrumentation, experimental conditions, retention times, fragmentation profiles and glycan structural diagnostic ion features) relevant for reliable data analyses. The GlycoRRT workflow was employed to map the N - and O - glycome in blood group matched human plasma and urine as well as decipher Immunoglobulin (IgG) glycosylation features from 13 different animal species. We have also developed visualization tools to enable a consistent, reliable, and reproducible analysis of large sets of multidimensional PGC-nLC-MS/MS glycomics data. This comprehensive glycan resource provides the glycan map of human and animal species, will serve as a reference in dissecting the role of glycans in host pathogen interaction and zoonotic disease transmission.
Publisher: Cold Spring Harbor Laboratory
Date: 15-03-2021
DOI: 10.1101/2021.03.14.435332
Abstract: Glycoproteome profiling (glycoproteomics) is a powerful yet analytically challenging research tool. The complex tandem mass spectra generated from glycopeptide mixtures require sophisticated analysis pipelines for structural determination. Diverse software aiding the process have appeared, but their relative performance remains untested. Conducted through the HUPO Human Proteome Project – Human Glycoproteomics Initiative, this community study, comprising both developers and users of glycoproteomics software, evaluates the performance of informatics solutions for system-wide glycopeptide analysis. Mass spectrometry-based glycoproteomics datasets from human serum were shared with all teams. The relative team performance for N - and O -glycopeptide data analysis was comprehensively established and validated through orthogonal performance tests. Excitingly, several high-performance glycoproteomics informatics solutions were identified. While the study illustrated that significant informatics challenges remain, as indicated by a high discordance between annotated glycopeptides, lists of high-confidence (consensus) glycopeptides were compiled from the standardised team reports. Deep analysis of the performance data revealed key performance-associated search variables and led to recommendations for improved “high coverage” and “high accuracy” glycoproteomics search strategies. This study concludes that erse software for comprehensive glycopeptide data analysis exist, points to several high-performance search strategies, and specifies key variables that may guide future software developments and assist informatics decision-making in glycoproteomics.
Publisher: Elsevier BV
Date: 03-2005
Publisher: Springer New York
Date: 15-10-2016
DOI: 10.1007/978-1-4939-6493-2_9
Abstract: The vast heterogeneity of protein glycosylation, even of a single glycoprotein with only one glycosylation site, can give rise to a set of macromolecules with different physicochemical properties. Thus, the use of orthogonal approaches for comprehensive characterization of glycoproteins is a key requirement. This chapter describes a universal workflow for site-specific N- and O-glycopeptide analysis. In a first step glycoproteins are treated with Pronase to generate glycopeptides containing small peptide sequences for enhanced glycosylation site assignment and characterization. These glycopeptides are then separated and detected using an integrated C18-porous graphitized carbon-liquid chromatography (PGC-LC) setup online coupled to a high-resolution electrospray ionization (ESI)-quadrupole time-of-flight (QTOF)-mass spectrometer operated in a combined higher- and lower-energy CID (stepping-energy CID) mode. The LC-setup allows retention of more hydrophobic glycopeptides on C18 followed by subsequent capturing of C18-unbound (glyco)peptides by a downstream placed PGC stationary phase. Glycopeptides eluted from both columns are then analyzed within a single analysis in a combined data acquisition mode. Stepping-energy CID results in B- and Y-ion fragments originating from the glycan moiety as well as b- and y-ions derived from the peptide part. This allows simultaneous site-specific identification of the glycan and peptide sequence of a glycoprotein.
Publisher: Portland Press Ltd.
Date: 08-10-2004
DOI: 10.1042/BJ20041062
Abstract: In Europe, hazelnuts (Corylus avellana) are a frequent cause of food allergies. Several important hazelnut allergens have been previously identified and characterized. Specific N-glycans are known to induce strong IgE responses of uncertain clinical relevance, but so far the allergenic potential of glycoproteins from hazelnut has not been investigated. The aim of the study was the molecular characterization of the glycosylated vicilin Cor a 11 from hazelnut and the analysis of its allergenic activity. Although MALDI–TOF (matrix-assisted laser-desorption ionization–time-of-flight) MS showed that one of two potential glycosylation sites of Cor a 11 was glycosylated, CD spectroscopy indicated that recombinant and natural Cor a 11 share similar secondary structures. Thus to analyse the impact of the glycan residues of Cor a 11 on IgE binding, the allergenic activity of natural glycosylated Cor a 11 and recombinant Cor a 11 was compared. In addition, the IgE sensitization pattern to recombinant Cor a 11, Cor a 1, Cor a 2 and Cor a 8 of 65 hazelnut allergic patients was determined in vitro. The prevalence of IgE reactivity to hazelnut vicilin Cor a 11 was below 50%. Basophil histamine-release assays were used to determine the allergenic activity of both natural and recombinant Cor a 11 in comparison with Cor a 1, a birch (Betula verrucosa) pollen-related major hazelnut allergen. Both forms of Cor a 11 induced mediator release from basophils to a similar extent, indicating that the hazelnut allergic patients had cross-linking IgE antibodies binding to the protein backbone and not to carbohydrate structures. In comparison to Cor a 1, a 10000-fold higher concentration of Cor a 11 was required to induce similar basophil mediator release. In conclusion, the hazelnut vicilin Cor a 11 is a minor allergen both in regard to prevalence and allergenic potency, whereas its glycan does not contribute to its allergenic activity.
Publisher: Elsevier BV
Date: 08-2011
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6CC01114D
Abstract: Differentiating the structure of isobaric glycopeptides represents a major challenge for mass spectrometry-based characterisation techniques.
Publisher: Wiley
Date: 31-07-2013
DOI: 10.1111/PBI.12096
Publisher: Cold Spring Harbor Laboratory
Date: 24-06-2019
DOI: 10.1101/676288
Abstract: We used a small synthetic glycopeptide library to systematically evaluate the effect of glycosylation site location and glycan size on the efficiency of ETD MS/MS fragmentation and subsequent automated identification. Understanding how the physico-chemical properties of glycopeptides influence glycopeptide fragmentation allows for optimizing fragmentation conditions and software assisted data analyses, which rely on informative fragmentation spectra for subsequent data processing to identify glycopeptides. Often, mis-assignment of glycopeptides occurs due to uncertainties such as failure to produce sufficient peptide backbone fragment ions. Our synthetic glycopeptide library contained glycopeptides differing in glycosylation site position within the peptide as well as glycan size (from the pentasaccharide N -glycan core to fully sialylated, biantennary N -glycans). Different software solutions such as SEQUEST and Amanda were compared for ETD glycopeptide identification. We found that all, glycan size, glycosylation site position within a glycopeptide and in idual precursor m/z significantly impacted the number and quality of assignable glycopeptide backbone fragments, and thus the likelihood to be correctly identified in software assisted data analyses.
Publisher: Elsevier BV
Date: 10-2016
DOI: 10.1016/J.MAM.2016.04.004
Abstract: Proteins are frequently modified by complex carbohydrates (glycans) that play central roles in maintaining the structural and functional integrity of cells and tissues in humans and lower organisms. Mannose forms an essential building block of protein glycosylation, and its functional involvement as components of larger and erse α-mannosidic glycoepitopes in important intra- and intercellular glycoimmunological processes is gaining recognition. With a focus on the mannose-rich asparagine (N-linked) glycosylation type, this review summarises the increasing volume of literature covering human and non-human protein mannosylation, including their structures, biosynthesis and spatiotemporal expression. The review also covers their known interactions with specialised host and microbial mannose-recognising C-type lectin receptors (mrCLRs) and antibodies (mrAbs) during inflammation and pathogen infection. Advances in molecular mapping technologies have recently revealed novel immuno-centric mannose-terminating truncated N-glycans, termed paucimannosylation, on human proteins. The cellular presentation of α-mannosidic glycoepitopes on N-glycoproteins appears tightly regulated α-mannose determinants are relative rare glycoepitopes in physiological extracellular environments, but may be actively secreted or leaked from cells to transmit potent signals when required. Simultaneously, our understanding of the molecular basis on the recognition of mannosidic epitopes by mrCLRs including DC-SIGN, mannose receptor, mannose binding lectin and mrAb is rapidly advancing, together with the functional implications of these interactions in facilitating an effective immune response during physiological and pathophysiological conditions. Ultimately, deciphering these complex mannose-based receptor-ligand interactions at the detailed molecular level will significantly advance our understanding of immunological disorders and infectious diseases, promoting the development of future therapeutics to improve patient clinical outcomes.
Publisher: Elsevier BV
Date: 04-2006
DOI: 10.1016/J.BBAGEN.2005.11.012
Abstract: The lecithinase homolog (Hev b 4) from Hevea brasiliensis (Q6T4P0_HEVBR) is an important natural rubber latex allergen. Hev b 4 is a highly glycosylated protein and its carbohydrate moiety has been implicated in the binding of IgE from natural rubber latex allergic patients. The cDNA for Hev b 4 has recently been cloned and sequenced. Here, we have analyzed the post-translational modifications of natural Hev b 4 by liquid chromatography/electrospray ionization-mass spectrometry of tryptic peptides. Seven of the eight potential glycosylation sites were found to be occupied. One site, however, was only partially glycosylated. Asn224 was substituted by complex type N-glycans with fucose and xylose, whereas all other sites carried either oligomannose glycans or a mixture of oligomannose and complex N-glycans. Glycosylation site Asn308, the most C-terminal one of the eight sites, was only found in the non-glycosylated form. The complex type N-glycans apparently form the molecular basis for the immune reaction with patients' sera. A large fraction of Hev b 4 molecules contains two or more complex N-glycans and thus a physiological reaction against these polyvalent allergens on the basis of the carbohydrate is in theory possible. Aside from allowing glycosylation analysis, the mass spectrometric data defined the N-terminal cleavage site of Hev b 4. This study once more demonstrates the outstanding analytical potential of electrospray ionization-mass spectrometry coupled with liquid chromatographic separation.
Publisher: Ivyspring International Publisher
Date: 2019
DOI: 10.7150/THNO.33858
Publisher: Wiley
Date: 16-04-2013
DOI: 10.1002/RCM.6527
Abstract: Glycosylation of proteins and lipids affects many biological processes, such as host-pathogen interactions, cell communication, and initiation of the immune responses. Terminal glycan substructures, or determinants, often govern the function or recognition of the carrier glycoconjugate and modulate these processes. In this study we describe a strategy using multistage mass spectrometry to identify and confirm these glycan substructures. An online tandem mass spectrometry (MS(2)) spectral fragment library of glycan substructures that typically occur at the non-reducing terminus of glycoconjugates was created to enable the easier identification and confirmation of glycan determinants on oligosaccharides released from glycoproteins. Oligosaccharides were separated by porous graphitized carbon capillary chromatography and analysed by ion trap MS. Candidate product ions that constitute the glycan substructure mass were identified in the MS(2) product ion spectrum, and used as the precursor ion for subsequent MS(3) fragmentation. The resulting MS(3) spectrum was matched against the MS(2) spectral fragment library to identify the glycan substructure(s) that comprise the parent oligosaccharide. Thirty biologically important terminal glycan determinants commonly observed on glycoconjugates were fragmented by positive and negative ion mass spectrometry and the MS(2) product ion masses manually annotated and stored in the UniCarb-DB online database. Negative ion tandem mass spectra were especially useful in assigning isobaric glycan structures. We have applied this strategy for the identification of the sulphation, blood group antigens and sialic acid linkages on complex N-and O-glycans released from glycoproteins. We show the potential of these glycan substructure MS(2) spectra in the negative ionization mode to facilitate the assignment of determinants on N- and O-linked glycans released from glycoproteins. Comparing the structural feature ions of known glycan reference substructures assists in the annotation of complex glycan product ion spectra, and can remove the need for other orthogonal confirmation analyses such as sequential glycosidase digestion.
Publisher: Oxford University Press (OUP)
Date: 26-03-2019
Abstract: The Minimum Information Required for a Glycomics Experiment (MIRAGE) is an initiative created by experts in the fields of glycobiology, glycoanalytics and glycoinformatics to design guidelines that improve the reporting and reproducibility of glycoanalytical methods. Previously, the MIRAGE Commission has published guidelines for describing s le preparation methods and the reporting of glycan array and mass spectrometry techniques and data collections. Here, we present the first version of guidelines that aim to improve the quality of the reporting of liquid chromatography (LC) glycan data in the scientific literature. These guidelines cover all aspects of instrument setup and modality of data handling and manipulation and is cross-linked with other MIRAGE recommendations. The most recent version of the MIRAGE-LC guidelines is freely available at the MIRAGE project website doi:10.3762/mirage.4.
Publisher: Wiley
Date: 07-2008
Abstract: Two LC-ESI-MS methods for the analysis of antibody glycosylation are presented. In the first approach, tryptic glycopeptides are separated by RP chromatography and analyzed by ESI-MS. This "glycopeptide strategy" allows a protein- and subclass-specific quantitation of both neutral and sialylated glycan structures. Additional information about under- or deglycosylation and the protein backbone, e.g., termini, can be extracted from the same data. In the second LC-ESI-MS method, released oligosaccharides are separated on porous graphitic carbon (PGC). A complete structural assignment of neutral and sialylated oligosaccharides occurring on antibodies is thereby achieved in one chromatographic run. The two methods were applied to polyclonal human IgG, to commercial mAb expressed in CHO cells (Rituximab, Xolair, and Herceptin), in SP2/0 (Erbitux and Remicade) or NS0 cells (Zenapax) and the anti-HIV antibody 4E10 produced either in CHO cells or in a human cell line. Both methods require comparably little s le preparation and can be applied to SDS-PAGE bands. They both outperform non-MS methods in terms of reliability of peak assignment and MALDI-MS of underivatized glycans with regard to the recording of sialylated structures. Regarding fast and yet detailed structural assignment, LC-MS on graphitic carbon supersedes all other current methods.
Publisher: Springer New York
Date: 2015
DOI: 10.1007/978-1-4939-2760-9_29
Abstract: The combination of porous graphitized carbon (PGC) liquid chromatography (LC) with mass spectrometric (MS) detection probably constitutes the most elaborate single stage analysis for isomer-specific N-glycan analysis. Here, we describe s le preparation and analysis procedures for the identification of released N-glycans using PGC-LC-ESI-MS and MS/MS.
Publisher: Wiley
Date: 2008
Abstract: Human butyrylcholinesterase (hBChE) is a highly glycosylated protein present in human plasma. The enzyme hydrolyses choline esters, for ex le benzoylcholine, butyrylthiocholine and acetylthiocholine as well as noncholine esters like heroin and aspirin. hBChE is primarily involved in neuronal transmission and is a potential bioscavenger of toxic organophosphates to protect acetylcholinesterase. A prerequisite for the therapeutic use of hBChE is a detailed characterization of this glycoprotein purified from human plasma. In this study, MS/MS could confirm most of the protein backbone, including the N- and the C-terminus. Site-specific analysis of all nine potential N-glycosylation sites revealed mainly mono- and disialylated N-glycans to be present on this glycoprotein. Sialic acids (Neu5Ac) are mainly alpha2,6-linked, however a fraction of the N-glycans contained Neu5Ac also in alpha2,3 linkage. On monosialylated N-glycans, sialic acid is exclusively located on the 3-arm and in alpha2,6 linkage, as verified by 2D-HPLC and exoglycosidase digests of 2-aminopyridine (PA)-labelled N-glycans. This first comprehensive glycoproteomic analysis of the important human plasma glycoprotein BChE did not give any indication of O-glycosylation or any other kind of PTMs as previously postulated.
Publisher: Springer Science and Business Media LLC
Date: 05-01-2006
DOI: 10.1007/S00425-005-0206-8
Abstract: The long held but challenged view that plants do not synthesize sialic acids was re-evaluated using two different procedures to isolate putative sialic acid containing material from plant tissues and cells. The extracts were reacted with 1,2-diamino-4,5-methylene dioxybenzene and the fluorescently labelled 2-keto sugar acids analysed by reversed phase and normal phase HPLC and by HPLC-electrospray tandem mass spectrometry. No N-glycolylneuraminic acid was found in the protein fraction from Arabidopsis thaliana MM2d cells. However, we did detect 3-deoxy-D: -manno-octulosonic acid and trace amounts (3-18 pmol/g fresh weight) of a compound indistinguishable from N-acetylneuraminic acid by its retention time and its mass spectral fragmentation pattern. Thus, plant cells and tissues contain five orders of magnitude less sialic acid than mammalian tissues such as porcine liver. Similar or lower amounts of N-acetylneuraminic acid were detected in tobacco cells, mung bean sprouts, apple and banana. Yet even yeast and buffer blanks, when subjected to the same isolation procedures, apparently contained the equivalent of 5 pmol of sialic acid per gram of material. Thus, we conclude that it is not possible to demonstrate unequivocally that plants synthesize sialic acids because the amounts of these sugars detected in plant cells and tissues are so small that they may originate from extraneous contaminants.
Publisher: Springer Science and Business Media LLC
Date: 22-07-2019
DOI: 10.1038/S41467-019-11131-X
Abstract: The mass spectrometry (MS)-based analysis of free polysaccharides and glycans released from proteins, lipids and proteoglycans increasingly relies on databases and software. Here, we review progress in the bioinformatics analysis of protein-released N - and O -linked glycans ( N - and O -glycomics) and propose an e-infrastructure to overcome current deficits in data and experimental transparency. This workflow enables the standardized submission of MS-based glycomics information into the public repository UniCarb-DR. It implements the MIRAGE (Minimum Requirement for A Glycomics Experiment) reporting guidelines, storage of unprocessed MS data in the GlycoPOST repository and glycan structure registration using the GlyTouCan registry, thereby supporting the development and extension of a glycan structure knowledgebase.
Publisher: Wiley
Date: 27-10-2006
DOI: 10.1111/J.1537-2995.2006.01004.X
Abstract: Isoelectric focusing (IEF) of alpha(1)-proteinase inhibitor (A1PI) shows that commercial products and plasma have different glycoisoform band patterns. Those in Aralast (Grifols Biologicals) reflect an anodal shift of glycoisoforms, which has caused concern. The protein, including glycoproteomic analyses, and structural features of A1PI products were investigated by state-of-the-art techniques. Batches from Aralast, Prolastin (Bayer), and Zemaira (Aventis Behring LLC) were analyzed by high-resolution IEF and high-performance size-exclusion chromatography (HP-SEC). Preparative separated isoforms from IEF were further purified by chromatography and subjected to mass spectrometry for sequence analyses, peptide mapping, and glycosylation analysis. Deamidation was quantified by enzymatic isoaspartate detection. Multiple sequence alignments and structural bioinformatics analyses were performed. In HP-SEC, Prolastin had the highest aggregate content at approximately 30 percent. Isoforms from all products purified by high-resolution IEF were sequenced with an amino acid coverage of more than 98 percent. Deamidation of Asn116 and Asn314 in A1PI was to found to some extent in all products and confirmed quantitatively by enzymatic analysis. There were no signs of methionine oxidation. Cys232 was found to be cysteinylated in A1PI in Prolastin and Aralast as in plasma, but not in Zemaira. All products showed truncation of the C-terminal lysine. Intact A1PI concentrates contained mainly diantennary, disialylated and smaller amounts of triantennary, trisialylated N-glycans. The percentage of fucosylation was similar in all products. Site-specific glycan analysis revealed bands M6 contained only diantennary glycans, whereas the more acidic bands M4 and M2 also carried triantennary structures. The most acidic isoforms, M2 in Prolastin and Zemaira and M0 in Aralast, additionally exhibited tetraantennary N-glycans. Protein chemical characterization of A1PI showed that all A1PI products to some extent differ from A1PI circulating in human plasma. Bioinformatic analysis indicated that removal of C-terminal Lys394 and cysteinylation of Cys232 are unlikely to affect structure and/or function of A1PI but cysteinylation may influence interaction between A1PI and its physiologic ligands. Aralast, Prolastin, and Zemaira contain the same set of N-glycans in the same ratios as those in normal human plasma A1PI. Tri- and tetraantennary structures are responsible for the partitioning into IEF isoforms, with the migration shift of Aralast not being due to any difference in the N-glycosylation, but to the partial loss of the C-terminal lysine.
Publisher: Springer Singapore
Date: 2018
DOI: 10.1007/978-981-13-2158-0_5
Abstract: In idual monosaccharides can be linked in a variety of different combinations to form complex glycoconjugates. In contrast to DNA and proteins, glycoconjugate synthesis does not follow any template but is the consequence of the concerted action of various enzymes such as transferases and glycosidases . Thus, tools for glycoconjugate sequencing need to differentiate in idual monosaccharide identity, linkage and anomericity to investigate and understand glycoconjugate function. In this chapter we provide a concise overview on the most commonly used and robust tools to separate and characterise glycoconjugate isomers.
Publisher: Elsevier BV
Date: 02-2011
Publisher: American Chemical Society (ACS)
Date: 06-01-2009
DOI: 10.1021/PR800910W
Abstract: Past proteomic studies of membrane proteins have often been h ered by the low abundance and relatively high hydrophobicity of these proteins. Proteins are often glycosylated, particularly on the extracellular surface of the plasma membrane, and this characteristic was targeted as an enrichment strategy for identifying membrane proteins. Here, we report a strategy for identifying the tissue membrane glycoproteome, which involves (1) Triton X-114 phase partitioning, (2) isolation of glycosylphosphatidylinositol (GPI)-anchored proteins, and (3) glycoprotein capture using lectin affinity or hydrazine chemistry. Surprisingly, the capture of membrane proteins by lectin affinity and hydrazine chemistry resulted in mostly different populations of enriched glycoproteins. Lectins enriched high molecular weight functional membrane proteins with more potential glycosylation such as those involved in signal transduction and cell adhesion. Conversely, hydrazine chemistry isolated a higher proportion of smaller, enzymatic and peripheral membrane proteins such as solute carrier transporters and cytochrome p450s. We have applied our strategy to characterize the rat liver membrane glycoproteome and identified four new predicted GPI-anchored proteins and two that have not previously been seen in the liver. We also identified 424 nonredundant membrane proteins, of which 335 had potential N-linked glycosylation sites.
Publisher: Wiley
Date: 20-11-2013
DOI: 10.1111/MMI.12455
Publisher: Elsevier BV
Date: 02-2011
Publisher: American Chemical Society (ACS)
Date: 20-04-2013
DOI: 10.1007/S13361-013-0610-4
Abstract: Glycomics is the comprehensive study of glycan expression in an organism, cell, or tissue that relies on effective analytical technologies to understand glycan structure-function relationships. Owing to the macro- and micro-heterogeneity of oligosaccharides, detailed structure characterization has required an orthogonal approach, such as a combination of specific exoglycosidase digestions, LC-MS/MS, and the development of bioinformatic resources to comprehensively profile a complex biological s le. Liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS/MS) has emerged as a key tool in the structural analysis of oligosaccharides because of its high sensitivity, resolution, and robustness. Here, we present a strategy that uses LC-ESI-MS/MS to characterize over 200 N- and O-glycans from human saliva glycoproteins, complemented by sequential exoglycosidase treatment, to further verify the annotated glycan structures. Fragment-specific substructure diagnostic ions were collated from an extensive screen of the literature available on the detailed structural characterization of oligosaccharides and, together with other specific glycan structure feature ions derived from cross-ring and glycosidic-linkage fragmentation, were used to characterize the glycans and differentiate isomers. The availability of such annotated mass spectrometric fragmentation spectral libraries of glycan structures, together with such substructure diagnostic ions, will be key inputs for the future development of the automated elucidation of oligosaccharide structures from MS/MS data.
Publisher: Springer Science and Business Media LLC
Date: 10-12-2021
Publisher: Elsevier BV
Date: 10-2013
Publisher: Cold Spring Harbor Laboratory
Date: 30-06-2021
DOI: 10.1101/2021.06.25.21259296
Abstract: B-cell precursor acute lymphoblastic leukemia (BCP-ALL) with mixed-lineage leukemia gene rearrangement (MLL-r) is a poor-prognosis subtype for which additional therapeutic targets are urgently needed. Currently no multi omics data set for primary MLL r patient cells exists that integrates transcriptomics, proteomics and glycomics to gain an inclusive picture of theranostic targets. We have integrated transcriptomics, proteomics and glycomics to i) obtain the first inclusive picture of primary patient BCP-ALL cells and identify molecular signatures that distinguish leukemic from normal precursor B-cells and ii) better understand the benefits and limitations of the applied technologies to deliver deep molecular sequence data across major cellular biopolymers. MLL-r cells feature an extensive remodelling of their glycocalyx, with increased levels of Core 2-type O-glycans and complex N-glycans as well as significant changes in sialylation and fucosylation. Notably, glycosaminoglycan remodelling from chondroitin sulfate to heparan sulfate was observed. A survival screen, to determine if glycan remodelling enzymes are redundant, identified MGAT1 and NGLY1, essential components of the N-glycosylation/degradation pathway, as highly relevant within this in vitro screening. OGT and OGA, unique enzymes that regulate intracellular O-GlcNAcylation, were also indispensable. Transcriptomics and proteomics further identified Fes and GALNT7-mediated glycosylation as possible therapeutic targets. While there is overall good correlation between transcriptomics and proteomics data, we demonstrate that a systematic combined multi- omics approach delivers important diagnostic information that is missed when applying a single omics technology. Apart from confirming well-known MLL-r BCP-ALL glycoprotein markers, our integrated multi-omics workflow discovered previously unidentified diagnostic/therapeutic protein targets.
Publisher: Springer Science and Business Media LLC
Date: 07-06-2012
Abstract: The comprehensive analysis of protein glycosylation is a major requirement for understanding glycoprotein function in biological systems, and is a prerequisite for producing recombinant glycoprotein therapeutics. This protocol describes workflows for the characterization of glycopeptides and their site-specific heterogeneity, showing ex les of the analysis of recombinant human erythropoietin (rHuEPO), α1-proteinase inhibitor (A1PI) and immunoglobulin (IgG). Glycoproteins of interest can be proteolytically digested either in solution or in-gel after electrophoretic separation, and the (glyco)peptides are analyzed by capillary/nano-liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). If required, specific glycopeptide enrichment steps, such as hydrophilic interaction liquid chromatography (HILIC), can also be performed. Particular emphasis is placed on data interpretation and the determination of site-specific glycan heterogeneity. The described workflow takes approximately 3-5 d, including s le preparation and data analysis. The data obtained from analyzing released glycans of rHuEPO and IgG, described in the second protocol of this series (10.1038/nprot.2012.063), provide complementary detailed glycan structural information that facilitates characterization of the glycopeptides.
Publisher: Springer Science and Business Media LLC
Date: 07-06-2012
Abstract: This protocol shows how to obtain a detailed glycan compositional and structural profile from purified glycoproteins or protein mixtures, and it can be used to distinguish different isobaric glycan isomers. Glycoproteins are immobilized on PVDF membranes before the N-glycans are enzymatically released by PNGase F, isolated and reduced. Subsequently, O-glycans are chemically released from the same protein spot by reductive β-elimination. After desalting with cation exchange microcolumns, the glycans are separated and analyzed by porous graphitized carbon liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). Optionally, the glycans can be treated with sialidases or other specific exoglycosidases to yield more detailed structural information. The s le preparation takes approximately 4 d, with a heavier workload on days 2 and 3, and a lighter load on days 1 and 4. The time for data interpretation depends on the complexity of the s les analyzed. This method can be used in conjunction with the analysis of enriched glycopeptides by capillary/nanoLC-ESI-MS/MS, which together provide detailed information regarding the site heterogeneity of glycosylation.
Publisher: Springer International Publishing
Date: 2020
DOI: 10.1007/10_2020_144
Publisher: Springer International Publishing
Date: 2020
DOI: 10.1007/10_2020_143
Publisher: Elsevier BV
Date: 2009
Abstract: Labeling of oligosaccharides with fluorescent dyes is the prerequisite for their sensitive analysis by high-performance liquid chromatography (HPLC). In this work, we present a fast new postlabeling cleanup procedure that requires no device other than the reaction vial itself. The procedure can be applied to essentially all labeling reagents. We also compare the performance of 15 different labels for N-glycan analysis in various analytical procedures. We took special care to prevent obscuring influences from incomplete derivatization and signal quenching by impurities. Procainamide emerged as more sensitive than anthranilic acid for normal-phase HPLC, but its chromatographic performance was not convincing. 2-aminopyridine was the label with the lowest retention on reversed-phase and graphitic carbon columns and, thus, appears to be most suitable for glycan fractionation by multidimensional HPLC. Most glycan derivatives performed better than native sugars in matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) and electrospray ionization-MS (ESI-MS), but the gain was small and hardly sufficient to compensate for s le loss during preparation.
Publisher: Elsevier BV
Date: 04-2003
DOI: 10.1067/MAI.2003.173
Abstract: The clinical relevance of IgE specific for cross-reactive carbohydrate determinants (CCDs) has been a matter of controversy. Until now, no convincing experiments have been performed to test the biologic significance of in idual multivalent allergens that carry multiple carbohydrate epitopes. We sought to contribute to the understanding of the role of CCD-specific IgE antibodies and to study whether CCD-specific IgE antibodies are able to activate basophils using different multivalent glycoproteins as antigens. Purified natural tomato beta-fructofuranosidase (nLyc e 2) and rLyc e 2.02 expressed in Escherichia coli were compared by means of histamine release tests. In addition, native and deglycosylated horseradish peroxidase and a neoglycoprotein consisting of a defined glycopeptide (Manalpha1-6[Xylbeta1-2]Manbeta1-4GlcNAcbeta1-4[Fucalpha1-3]GlcNAc) coupled to BSA were used in histamine release assays using stripped basophils from normal donors resensitized with IgE from CCD-reactive patients with food allergy to tomato. Ten CCD-positive and 2 CCD-negative sera from patients with tomato allergy underwent histamine release testing by using the glycoproteins and nonglycosylated controls as antigens, respectively. All sera induced histamine release with tomato extract (up to 100%), confirming the allergic status of the donors. Four of the CCD-positive sera induced releases ranging from 12% to 82% with all of the glycoproteins but not with the nonglycosylated or monovalent controls. All other sera showed no response or only very weak response to the glycoproteins. Approximately one third of the CCD-positive sera from patients with tomato allergy have biologically relevant CCD-specific IgE antibodies. Therefore the general claim that CCD-specific IgE is clinically irrelevant has to be reconsidered critically. Hence IgE specific for CCDs should be taken into consideration in the diagnosis and therapy of certain allergies. In the subgroup of patients sensitized to CCDs, the use of natural allergens should be preferred over the use of recombinant allergens expressed in prokaryotic organisms.
Publisher: Ivyspring International Publisher
Date: 2021
DOI: 10.7150/THNO.65398
Publisher: Elsevier BV
Date: 09-2011
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D0MO90019B
Abstract: Morten Thaysen-Andersen, Daniel Kolarich and Nicolle H. Packer introduce the Molecular Omics themed issue on Glycomics & Glycoproteomics: From Analytics to Function.
Publisher: Springer Science and Business Media LLC
Date: 12-2016
Publisher: Springer Science and Business Media LLC
Date: 28-10-2015
Publisher: Elsevier BV
Date: 2020
Publisher: American Society for Microbiology
Date: 10-2006
DOI: 10.1128/CVI.00125-06
Abstract: Iron limitation and the expression of mycobactin and carboxymycobactin by Mycobacterium tuberculosis are known. Here, we report how iron regulated the coordinate expression of these two siderophores and a 28-kDa cell wall-associated iron-regulated protein (Irep-28). Irep-28 is identified as the DNA-binding HU homologue HupB protein ( hupB [Rv2986c]). Antibodies to this protein were detected in sera from tuberculosis patients. The location of the protein in the cell wall makes it a potential drug target.
Publisher: Springer Science and Business Media LLC
Date: 10-10-2013
DOI: 10.1007/S10719-012-9452-8
Abstract: As one of several biologically active compounds in milk, glycoproteins have been indicated to be involved in the protection of newborns from bacterial infection. As much of the physical and immune development of the tammar wallaby (Macropus eugenii) young occurs during the early phases of lactation and not in utero, the tammar is a model species for the characterization of potential developmental support agents provided by maternal milk.In the present study, the N- and O-linked glycans from tammar wallaby milk glycoproteins from six in iduals at different lactation time points were subjected to glycomics analyses using porous graphitized carbon liquid chromatography electrospray ionization mass spectrometry. Structural characterization identified a erse range of glycan structures on wallaby milk glycoproteins including sialylated, sulphated, core fucosylated and O-fucosylated structures. 30 % of N-linked structures contained a core (α1-6) fucose. Several of these structures may play roles in development, and exhibit statistically significant temporal changes over the lactation period. The N-glycome was found to contain structures with NeuGc residues, while in contrast the O-glycome did not. O-fucosylated structures were identified in the early stages of lactation indicating a potential role in the early stages of development of the pouch young. Overall the results suggest that wallaby milk contains structures known to have developmental and immunological significance in human milk and reproduction in other animals, highlighting the importance of glycoproteins in milk.
Publisher: Oxford University Press (OUP)
Date: 09-2016
Abstract: The minimum information required for a glycomics experiment (MIRAGE) project was established in 2011 to provide guidelines to aid in data reporting from all types of experiments in glycomics research including mass spectrometry (MS), liquid chromatography, glycan arrays, data handling and s le preparation. MIRAGE is a concerted effort of the wider glycomics community that considers the adaptation of reporting guidelines as an important step towards critical evaluation and dissemination of datasets as well as broadening of experimental techniques worldwide. The MIRAGE Commission published reporting guidelines for MS data and here we outline guidelines for s le preparation. The s le preparation guidelines include all aspects of s le generation, purification and modification from biological and/or synthetic carbohydrate material. The application of MIRAGE s le preparation guidelines will lead to improved recording of experimental protocols and reporting of understandable and reproducible glycomics datasets.
Publisher: Frontiers Media SA
Date: 16-11-2021
DOI: 10.3389/FMICB.2021.734526
Abstract: C ylobacter jejuni is a common cause of diarrheal disease worldwide. Human infection typically occurs through the ingestion of contaminated poultry products. We previously demonstrated that an attenuated Escherichia coli live vaccine strain expressing the C. jejuni N-glycan on its surface reduced the C ylobacter load in more than 50% of vaccinated leghorn and broiler birds to undetectable levels (responder birds), whereas the remainder of the animals was still colonized (non-responders). To understand the underlying mechanism, we conducted three vaccination and challenge studies using 135 broiler birds and found a similar responder/non-responder effect. Subsequent genome-wide association studies (GWAS), analyses of bird sex and levels of vaccine-induced IgY responses did not correlate with the responder versus non-responder phenotype. In contrast, antibodies isolated from responder birds displayed a higher C ylobacter -opsonophagocytic activity when compared to antisera from non-responder birds. No differences in the N-glycome of the sera could be detected, although minor changes in IgY glycosylation warrant further investigation. As reported before, the composition of the microbiota, particularly levels of OTU classified as Clostridium spp., Ruminococcaceae and Lachnospiraceae are associated with the response. Transplantation of the cecal microbiota of responder birds into new birds in combination with vaccination resulted in further increases in vaccine-induced antigen-specific IgY responses when compared to birds that did not receive microbiota transplants. Our work suggests that the IgY effector function and microbiota contribute to the efficacy of the E. coli live vaccine, information that could form the basis for the development of improved vaccines targeted at the elimination of C. jejuni from poultry.
Publisher: Frontiers Media SA
Date: 21-03-2018
Publisher: Microbiology Society
Date: 03-2014
Abstract: Members of the genus Bacteroides , mainly Bacteroides fragilis , can cause severe disease in man, especially after intestinal perforation in the course of abdominal surgery. Treatment is based on a small number of antibiotics, including metronidazole, which has proved to be highly reliable throughout the last 40 to 50 years. Nevertheless, metronidazole resistance does occur in Bacteroides and has been mainly attributed to Nim proteins, a class of proteins with a suggested nitroreductase function. Despite the potentially high importance of Nim proteins for human health, information on the expression of nim genes in B. fragilis is still lacking. It was the aim of this study to demonstrate expression of nim genes in B. fragilis at the protein level and, furthermore, to correlate Nim levels with the magnitude of metronidazole resistance. By the application of 2D gel electrophoresis, Nim proteins could be readily identified in nim -positive strains, but their levels were not elevated to a relevant extent after induction of resistance with high doses of metronidazole. Thus, the data herein do not provide evidence for Nim proteins acting as nitroreductases using metronidazole as a substrate, because no correlation between Nim levels and levels of metronidazole resistance could be observed. Furthermore, no evidence was found that Nim proteins protect B . fragilis from metronidazole by sequestering the activated antibiotic.
Publisher: Springer Science and Business Media LLC
Date: 17-09-2017
DOI: 10.1007/S10719-016-9726-7
Abstract: Human blood group polymorphisms are known to be determined by the expression of A, B or H antigens and the Lewis antigens. Protection against microbial infections has been associated with inheritance of polymorphisms in genes encoding and regulating the expression of ABH and Lewis antigens in bodily secretions and epithelial tissue surfaces, subsequently resulting in the presentation of different glycosylated terminal antigens on the cell surface. We investigated the role of blood group antigens in ersifying the glycosylation of buccal epithelial cells (BEC) that line the oral cavity. Specifically, we characterized and statistically evaluated the expression of histo-blood group (A, B, O) antigens on N-and O-linked glycans from BEC membrane proteins of various in iduals that represented different blood group type and secretor status using a porous graphitic carbon liquid chromatography electrospray ionization mass spectrometry (PGC-LC-ESI-MS) based glycomics approach. From these BEC membrane proteins a total of 77 N-glycan and 96 O-glycan structures were structurally characterized from 19 in iduals and relatively quantitated. The N-glycans from the secretor in iduals did not express any A/B blood group determinants, but contained several terminal H-antigens. Apart from the non-secretors, the N-glycan profiles of BEC from all blood groups displayed similar glycan types, while varying in their relative intensities between in iduals. However, multivariate analysis of the O-glycans from in iduals displayed segregation patterns clearly associated with their blood group type and secretor status. In adhesion assays the oral pathogen Candida albicans showed a significantly higher interaction to blood group O type BECs relative to other blood groups.
Publisher: Springer Science and Business Media LLC
Date: 23-03-2012
DOI: 10.1007/S11103-012-9902-5
Abstract: Processes associated with late events of N-glycosylation within the plant Golgi complex are a major limitation to the use of plant-based systems to produce recombinant pharmaceutical proteins for parenteral administration. Specifically, sugars added to the N-glycans of a recombinant protein during glycan maturation to complex forms (e.g. β1,2 xylose and α1,3 fucose) can render the product immunogenic. In order to avoid these sugars, the human enzyme α-L-iduronidase (IDUA, EC 3.2.1.76), with a C-terminal ER-retention sequence SEKDEL, was expressed in seeds of complex-glycan-deficient (cgl) mutant and wild-type (Col-0) Arabidopsis thaliana, under the control of regulatory (5'-, signal-peptide-encoding-, and 3'-) sequences from the arcelin 5-I gene of Phaseolus vulgaris (cgl-IDUA-SEKDEL and Col-IDUA-SEKDEL, respectively). The SEKDEL motif had no adverse effect on the specific activity of the purified enzyme. Surprisingly, the majority of the N-glycans of Col-IDUA-SEKDEL were complex N-glycans (i.e. contained xylose and/or fucose) (88 %), whereas complex N-glycans comprised a much lower proportion of the N-glycans of cgl-IDUA-SEKDEL (26 %), in which high-mannose forms were predominant. In contrast to the non-chimeric IDUA of cgl seeds, which is mainly secreted into the extracellular spaces, the addition of the SEKDEL sequence to human recombinant IDUA expressed in the same background led to retention of the protein in ER-derived vesicles/compartments and its partial localization in protein storage vacuoles. Our data support the contention that the use of a C-terminal ER retention motif as an effective strategy to prevent or reduce complex N-glycan formation, is protein specific.
Publisher: Oxford University Press (OUP)
Date: 22-11-2016
Publisher: Springer Science and Business Media LLC
Date: 09-12-2014
Publisher: Elsevier BV
Date: 08-2016
DOI: 10.1016/J.BBAGEN.2015.12.016
Abstract: Terminal α2-3 and α2-6 sialylation of glycans precludes further chain elongation, leading to the biosynthesis of cancer relevant epitopes such as sialyl-Lewis X (SLe(X)). SLe(X) overexpression is associated with tumor aggressive phenotype and patients' poor prognosis. MKN45 gastric carcinoma cells transfected with the sialyltransferase ST3GAL4 were established as a model overexpressing sialylated terminal glycans. We have evaluated at the structural level the glycome and the sialoproteome of this gastric cancer cell line applying liquid chromatography and mass spectrometry. We further validated an identified target expression by proximity ligation assay in gastric tumors. Our results showed that ST3GAL4 overexpression leads to several glycosylation alterations, including reduced O-glycan extension and decreased bisected and increased branched N-glycans. A shift from α2-6 towards α2-3 linked sialylated N-glycans was also observed. Sialoproteomic analysis further identified 47 proteins with significantly increased sialylated N-glycans. These included integrins, insulin receptor, carcinoembryonic antigens and RON receptor tyrosine kinase, which are proteins known to be key players in malignancy. Further analysis of RON confirmed its modification with SLe(X) and the concomitant activation. SLe(X) and RON co-expression was validated in gastric tumors. The overexpression of ST3GAL4 interferes with the overall glycophenotype of cancer cells affecting a multitude of key proteins involved in malignancy. Aberrant glycosylation of the RON receptor was shown as an alternative mechanism of oncogenic activation. This study provides novel targets and points to an integrative tumor glycomic roteomic-profiling for gastric cancer patients' stratification. This article is part of a Special Issue entitled "Glycans in personalised medicine" Guest Editor: Professor Gordan Lauc.
Publisher: Frontiers Media SA
Date: 28-08-2018
Publisher: Wiley
Date: 03-2003
DOI: 10.1046/J.1432-1033.2003.03503.X
Abstract: Until now, only a small amount of information is available about tomato allergens. In the present study, a glycosylated allergen of tomato (Lycopersicon esculentum), Lyc e 2, was purified from tomato extract by a two-step FPLC method. The cDNA of two different isoforms of the protein, Lyc e 2.01 and Lyc e 2.02, was cloned into the bacterial expression vector pET100D. The recombinant proteins were purified by electroelution and refolded. The IgE reactivity of both the recombinant and the natural proteins was investigated with sera of patients with adverse reactions to tomato. IgE-binding to natural Lyc e 2 was completely inhibited by the pineapple stem bromelain glycopeptide MUXF (Man alpha 1-6(Xyl beta 1-2)Man beta 1-4GlcNAc beta 1-4(Fuc alpha 1-3)GlcNAc). Accordingly, the nonglycosylated recombinant protein isoforms did not bind IgE of tomato allergic patients. Hence, we concluded that the IgE reactivity of the natural protein mainly depends on the glycan structure. The amino acid sequences of both isoforms of the allergen contain four possible N-glycosylation sites. By application of MALDI-TOF mass spectrometry the predominant glycan structure of the natural allergen was identified as MMXF (Man alpha 1-6(Man alpha 1-3)(Xyl beta 1-2)Man beta 1-4GlcNAc beta 1-4(Fuc alpha 1-3) GlcNAc). Natural Lyc e 2, but not the recombinant protein was able to trigger histamine release from passively sensitized basophils of patients with IgE to carbohydrate determinants, demonstrating that glycan structures can be important for the biological activity of allergens.
Publisher: Springer Science and Business Media LLC
Date: 27-10-2022
DOI: 10.1007/S00216-022-04376-X
Abstract: Glycosylation is the most common post-translational modification of proteins, and glycosylation changes at cell surfaces are frequently associated with malignant epithelia including head and neck squamous cell carcinoma (HNSCC). In HNSCC, 5-year survival remains poor, averaging around 50% globally: this is partly related to late diagnosis. Specific protein glycosylation signatures on malignant keratinocytes have promise as diagnostic and prognostic biomarkers and as therapeutic targets. Nevertheless, HNSCC-specific glycome is to date largely unknown. Herein, we tested six established HNSCC cell lines to capture the qualitative and semi-quantitative N-glycome using porous graphitized carbon liquid chromatography coupled to electrospray ionisation tandem mass spectrometry. Oligomannose-type N-glycans were the predominant features in all HNSCC cell lines analysed (57.5–70%). The levels of sialylated N-glycans showed considerable cell line-dependent differences ranging from 24 to 35%. Importantly, α2-6 linked sialylated N-glycans were dominant across most HNSCC cell lines except in SCC-9 cells where similar levels of α2-6 and α2-3 sialylated N-glycans were observed. Furthermore, we found that HPV-positive cell lines contained higher levels of phosphorylated oligomannose N-glycans, which hint towards an upregulation of lysosomal pathways. Almost all fucose-type N-glycans carried core-fucose residues with just minor levels ( 4%) of Lewis-type fucosylation identified. We also observed paucimannose-type N-glycans (2–5.5%), though in low levels. Finally, we identified oligomannose N-glycans carrying core-fucose residues and confirmed their structure by tandem mass spectrometry. This first systematic mapping of the N-glycome revealed erse and specific glycosylation features in HNSCC, paving the way for further studies aimed at assessing their possible diagnostic relevance.
Publisher: Elsevier BV
Date: 04-2017
Publisher: Beilstein Institut
Date: 09-11-2021
DOI: 10.3762/BJOC.17.184
Publisher: Wiley
Date: 06-2006
Abstract: Human alpha1-antitrypsin (A1PI) is a well-known glycoprotein in human plasma important for the protection of tissues from proteolytic enzymes. The three N-glycosylation sites of A1PI contain diantennary N-glycans but also triantennary and even traces of tetraantennary structures leading to the typical IEF pattern observed for A1PI. Here we present an approach to characterize A1PI isoforms from human plasma and its PTMs by LC-ESI-MS and LC-ESI-MS/MS of peptides obtained by proteolytic digestion. The single cysteine residue of A1PI formed a disulfide bridge with free cysteine. The variability of the number of antennae and hence sialic acids on glycosylation site N107, which even contained minute amounts of tetraantennary structures, emerged as a major cause for the IEF pattern of A1PI. Only negligible amounts of triantennary structures were identified attached to N70, and exclusively diantennary structures were present on site N271 in each of the isoforms analyzed. Exoglycosidase digests revealed alpha2,6-linked neuraminic acids on diantennary N-glycans, and triantennary contained additionally one single alpha2,3-neuraminic acid per N-glycan, which, together with a fucose, formed a sialyl Lewis X determinant on the beta1,4-linked N-acetylglucosamine, as shown by 2-D-HPLC of pyridylaminated asialoglycans. Fucosylation of diantennary structures was marginal and of the core alpha1,6 type.
Publisher: Elsevier BV
Date: 06-2016
Publisher: Elsevier BV
Date: 11-2012
DOI: 10.1016/J.VETPAR.2012.05.011
Abstract: The 5-nitroimidazole, metronidazole, has traditionally been employed in veterinary medicine to treat a range of infections including the diplomonad fish parasite Spironucleus. This study aims to determine the mode of action of metronidazole on Spironucleus vortens, including the specific mechanism of activation of the pro-drug and subsequent cellular targets of the drug metabolites. Due to the ban on use of metronidazole in the treatment of production animals in Europe and USA, garlic-derived compounds were also investigated as natural alternatives to metronidazole chemotherapy. Scanning electron microscopy (SEM) provided an overview of gross cellular damage caused by metronidazole and garlic derivatives. Proteomic analyses by 2D gel electrophoresis identified the proteins involved in specific covalent adduct formation with nitroimidazoles. Furthermore, thioredoxin reductase (TrxR) activity and non-protein thiol concentration were assayed in extracts of S. vortens before and after treatment with nitroimidazoles and garlic-derivatives. Metronidazole and garlic-derived compounds caused severe damage of trophozoites indicated by membrane blebbing and lysed cell debris. Analysis of the S. vortens proteome identified several proteins capable of specific nitroimidazole binding, including uridine phosphorylase, enolase, protein disulphide isomerase, aminoacyl-histidine dipeptidase and malic enzyme. Of the compounds tested, metronidazole and the garlic-derived compound ajoene were the most effective at inhibiting TrxR activity and depleting non-protein thiols. These data suggest TrxR-mediated activation of nitroimidazoles, leading to depletion of non-protein thiols. Redox imbalance due to antioxidant failure is implicated as the mode of action of nitroimidazoles and garlic-derived compounds, ultimately leading to cell death. Possible synergy between garlic derivatives and metronidazole should be further investigated in vitro in order to determine their theoretical implications.
Publisher: Walter de Gruyter GmbH
Date: 14-01-2004
DOI: 10.1515/BC.2004.044
Publisher: Elsevier BV
Date: 06-2012
Publisher: Elsevier BV
Date: 05-2005
Publisher: Wiley
Date: 05-2007
Abstract: The venoms of stinging insects belong to the most dangerous allergen sources and can cause fatal anaphylactic reactions. Reliable prediction of a patient's risk to anaphylactic reactions is vital, and diagnosis requires the knowledge of the relevant allergens. Recently, a new hyaluronidase -like glycoprotein from Vespula vulgaris (Ves v 2b) was identified. This led us to investigate hyaluronidases and also other major allergens from V. germanica and four additional Vespula species. By MALDI-Q-TOF-MS, the new hyaluronidase-like protein was shown to be the major component of the 43-kDa band in all Vespula species studied. LC-ESI-Q-TOF-MS/MS sequencing of Ves g 2a and Ves g 2b facilitated the cloning of their cDNA. Ves v 2b and Ves g 2b turned out to be essentially identical on protein level. Whereas the less abundant "a" form displayed enzymatic activity, the new "b" homologue did not. This is probably caused by amino acid exchanges in the active site, and it raises questions about the physiological role of this protein. Sequence comparisons by MS/MS of antigen 5 and phospholipases from V. vulgaris, germanica, maculifrons, pensylvanica, flavopilosa and squamosa revealed the latter as a taxonomic outlier and led to the discovery of several not previously reported amino acid differences.
Publisher: Springer Science and Business Media LLC
Date: 21-10-2019
DOI: 10.1007/S10719-019-09888-W
Abstract: We established a small synthetic N-glycopeptide library to systematically evaluate the effect of glycosylation site location and glycan size on the efficiency of electron transfer dissociation (ETD) fragmentation and subsequent automated identification. The glycopeptides within this library differed in glycosylation site position and glycan size ranging from the pentasaccharide N-glycan core to fully sialylated, biantennary N-glycans. Factors such as glycan size, glycosylation site position within a glycopeptide and in idual precursor m/z all significantly impacted the number and quality of assignable glycopeptide backbone fragments. Generally, high charge/low m/z precursors (>3+) and glycopeptides carrying neutral, smaller N-glycans gave better product ion spectra, while hardly any product ions were detectable for sialylated, triply charged N-glycopeptides. These factors impacted correct glycopeptide identification by proteomics software tools such as SEQUEST or Amanda. A better understanding how glycopeptide physico-chemical properties influence fragmentation will help optimizing fragmentation conditions and generate better data, which will facilitate software assisted glycopeptide data analyses.
Publisher: Springer Science and Business Media LLC
Date: 20-07-2015
DOI: 10.1038/ONC.2015.225
Publisher: Springer Science and Business Media LLC
Date: 04-02-2016
DOI: 10.1038/SREP20488
Abstract: Production of glycoconjugate vaccines involves the chemical conjugation of glycans to an immunogenic carrier protein such as Cross-Reactive-Material-197 (CRM 197 ). Instead of using glycans from natural sources recent vaccine development has been focusing on the use of synthetically defined minimal epitopes. While the glycan is structurally defined, the attachment sites on the protein are not. Fully characterized conjugates and batch-to-batch comparisons are the key to eventually create completely defined conjugates. A variety of glycoconjugates consisting of CRM 197 and synthetic oligosaccharide epitopes was characterised using mass spectrometry techniques. The primary structure was assessed by combining intact protein MALDI-TOF-MS, LC-MALDI-TOF-MS middle-down and LC-ESI-MS bottom-up approaches. The middle-down approach on CNBr cleaved glycopeptides provided almost complete sequence coverage, facilitating rapid batch-to-batch comparisons, resolving glycan loading and identification of side products. Regions close to the N- and C-termini were most efficiently conjugated.
Publisher: Elsevier BV
Date: 10-2000
Publisher: Elsevier BV
Date: 08-2011
Publisher: Elsevier BV
Date: 04-2012
DOI: 10.1016/J.CBPA.2011.12.006
Abstract: Glycomics and glycoproteomics have become indispensible tools in the study of glycoconjugates. Mass spectrometry based methods are standardly used to study the proteome and/or glycome and these approaches are capable of providing both, qualitative and quantitative information using top down techniques. The human immune system marks a particular area of interest for glycomics and glycoproteomics research since a large number of key proteins in innate and adaptive immunity are glycoproteins. In numerous ex les, the crucial influence of glycosylation on critical steps such as receptor interaction and binding has been demonstrated. In this review, we focus on different glycomics and glycoproteomics approaches and their application for studying protein glycosylation in the immune system.
Publisher: Elsevier BV
Date: 04-2014
DOI: 10.1016/J.JPROT.2014.02.018
Abstract: Haptoglobin (Hp) and immunoglobulins are plasma glycoproteins involved in the immune reaction of the organism after infection and/or inflammation. Porcine circovirus type 2-systemic disease (PCV2-SD), formerly known as postweaning multisystemic wasting syndrome (PMWS), is a globally spread pig disease of great economic impact. PCV2-SD affects the immunological system of pigs causing immunosuppression. The aim of this work was to characterize the Hp protein species of healthy and PCV2-SD affected pigs, as well as the protein backbone and the glycan chain composition of porcine Hp. PCV2-SD affected pigs had an increased overall Hp level, but it did not affect the ratio between Hp species. Glycoproteomic analysis of the Hp β subunits confirmed that porcine Hp is N-glycosylated and, unexpectedly, O-glycosylated, a PTM that is not found on Hp from healthy humans. The glyco-profile of porcine IgG and IgA heavy chains was also characterized decreased levels of both proteins were found in the investigated group of PCV2-SD affected pigs. Obtained results indicate that no significant changes in the N- and O-glycosylation patterns of these major porcine plasma glycoproteins were detectable between healthy and PCV2-SD affected animals. PCV2-SD is a disease of great economic importance for pig production, characterized by a complex response of the immune system. In the search of a better diagnostic rognostic marker for porcine PCV2-SD, extensive analyses of the Hp protein backbone and the glycan chains were thoroughly analyzed by various techniques. This resulted in detection and confirmation of Hp O-glycosylation and the glyco-profiling of porcine IgG and IgA. The N- and O-glycosylation of these major porcine plasma glycoproteins appears to be not affected by PCV2-SD infection. Interestingly, these data suggest that this viral infection, which significantly affects the immune responses of the host, leaves the biosynthetic glycosylation processes in the liver and immune cells unaffected. Lack of PTM changes is in contrast to findings in humans where for both proteins pattern changes have been reported in several chronic and inflammatory diseases. This underlines the importance of studying species in detail and not reaching to conclusions by analogy. Furthermore, since Hp is usually quantified by immunoassays in clinical routine analyses, our findings indicate that no bias in Hp determination capabilities due to an altered carbohydrate pattern is to be expected.
Publisher: Springer Science and Business Media LLC
Date: 04-06-2018
Publisher: Wiley
Date: 02-2007
Abstract: The importance of apple allergens has been repeatedly emphasized, and their presence has been confirmed both in pollen and in fruits. In the present study, a combination of proteomic tools have been used to build a complete allergen map of apple. The water-soluble fraction of an apple extract was precipitated using a phenol-based procedure and separated by 2-DE. Initially four previously classified allergens, Mal d 1, Mal d 2, Mal d 3 and Mal d 4, could be identified in Western blots with polyclonal rabbit antibodies directed to the four respective allergens, and subsequently matched to the bands recognized by several patient sera. Further, all four known apple allergens were localized on a 2-DE map and they were matched with spots recognized by sera of patients with different allergic patterns. Moreover, a new, putative allergen could be identified using MS. We evaluated the influence of post-translational modifications and the immunoreactivity under different analytical conditions. The comparison of different visualization methods for 2-DE gels and blots revealed that even very low concentrations of the intact epitopes are detectable by IgEs of patients, and therefore might be sufficient to trigger allergic symptoms in sensitized in iduals.
Publisher: Cold Spring Harbor Laboratory
Date: 24-11-2019
DOI: 10.1101/853036
Abstract: Glycan identification and characterisation is essential to correlate glycoconjugate structure to biological function. The structural assignment of carbohydrates is often based on MS composition analyses and knowledge on well-studied glycosylation pathways. Nevertheless, many monosaccharide building blocks are indistinguishable by mass alone and detailed linkage information is also not easily obtained by MS/MS analyses, in particular when organisms are studied where the glycosylation pathways are less well defined. Here, we present a novel, simple and sensitive method using Reversed Phase (RP) – Liquid Chromatography Electrospray ionisation tandem mass spectrometry (LC–ESI-MS/MS) for unambiguous identification and linkage determination of monosaccharides including N-acetylneuraminic acids. Sequential permethylation and reductive amination steps are employed prior and after acid hydrolysis to enable separation and differentiation of the various monosaccharides and their respective linkage positions. The well-established, monosaccharide specific methylation patterns allowed for the identification of the various derivatised monosaccharide alditols based on their retention time and tandem mass spectrometry fingerprint. Absolute quantitation can also be accomplished by including a set of internal standards, thus simultaneously providing qualitative and quantitative information on the monosaccharide residues present.
Publisher: Future Science Ltd
Date: 06-2013
DOI: 10.4155/BIO.13.97
Publisher: Elsevier BV
Date: 12-2001
Abstract: Up to 50% of patients with stinging-insect allergy have double-positive RAST results to honeybee and yellow jacket (YJ) venom. True double sensitization and crossreactivity through venom hyaluronidases are considered main reasons for this multiple reactivity. We investigated the role of antibodies against cross-reactive carbohydrate determinants in venom double positivity. CAP inhibition experiments were performed with crude oilseed rape (OSR) and timothy grass pollen extracts and a neoglycoprotein construct displaying a MUXF glycan, as present in pineapple-stem bromelain (MUXF-BSA). CAP to OSR was used as a rough measure for carbohydrate-specific IgE in in idual sera. CAP results to OSR pollen were positive in 2 of 14 single-positive honeybee venom sera, 2 of 16 single-positive YJ venom sera, and 33 (80.5%) of 41 double-positive sera (P CAP score to second venom), pollen extracts, MUXF-BSA, or both were able to completely inhibit IgE binding to one of the venoms, whereas this was not the case in 5 patients with a negative or weakly positive CAP result to OSR (CAP score to OSR < CAP score to second venom). The data suggest that carbohydrate-specific IgE is a major cause for the double positivity to honeybee and YJ venom seen in patients with Hymenoptera allergy. Because these antibodies may have low clinical relevance, they may severely impede the correct diagnosis of Hymenoptera venom allergy.
Publisher: Elsevier BV
Date: 2017
Publisher: Elsevier BV
Date: 05-2010
DOI: 10.1016/J.MOLBIOPARA.2010.01.001
Abstract: Infections with the microaerophilic protozoan parasite Trichomonas vaginalis are commonly treated with metronidazole, a 5-nitroimidazole drug. Metronidazole is selectively toxic to microaerophiles and anaerobes because reduction at the drug's nitro group, which is a precondition for toxicity, occurs only quantitatively in these organisms. In our previous work we identified the flavin enzyme thioredoxin reductase as an electron donor to 5-nitroimidazole drugs in T. vaginalis and observed that highly metronidazole-resistant cell lines lack thioredoxin reductase and flavin reductase activities. In this study we added the flavin inhibitor diphenyleneiodonium (DPI) to T. vaginalis cultures in order to test our hypothesis that metronidazole reduction is catalyzed by flavin enzymes, e.g. thioredoxin reductase, and intracellular free flavins. Indeed, within hours, DPI rendered T. vaginalis insensitive to metronidazole concentrations as high as 1mM and prevented the formation of metronidazole adducts with proteins. Thioredoxin reductase activity was absent from DPI-treated cells and flavin reductase activity was sharply decreased. In addition, DPI-treated cells also upregulated the expression of antioxidant enzymes, i.e. thioredoxin peroxidases and superoxide dismutases, and displayed a fundamentally altered metabolism caused by inactivation of pyruvate:ferredoxin oxidoreductase (PFOR) and concomitant upregulation of lactate dehydrogenase (LDH) activity. Thus, the disruption of the cellular flavin metabolism by DPI mediated metabolic steps which are similar to that of cells with metronidazole resistance induced in vitro. Finally, we present direct evidence that the increased expression of antioxidant enzymes is dispensable for acquiring resistance to metronidazole.
Publisher: Springer Japan
Date: 20-10-2014
Publisher: CRC Press
Date: 27-09-2012
DOI: 10.1201/B12965
Publisher: Oxford University Press (OUP)
Date: 24-09-2015
Publisher: Springer New York
Date: 15-10-2016
DOI: 10.1007/978-1-4939-6493-2_11
Abstract: The availability of well-defined s les in sufficient numbers represents a major bottleneck for any biomarker related research. The utilization of preserved, archived and clinically well-described s les therefore holds a great potential to bridge this gap. This chapter describes a universal workflow for the comprehensive characterization of N- and O-glycans released from whole formalin-fixed, paraffin-embedded tissue sections, including an option for further partitioning using laser microdissection of specific tissue areas/cell populations. Glycoproteins are extracted and subsequently immobilized onto a PVDF membrane prior enzymatic release of N-glycans. Following N-glycan retrieval O-glycans are released using reductive β-elimination from the same s le spot, significantly reducing the required amount of starting material. Released and reduced glycan structures are characterized using porous graphitized carbon liquid chromatography online coupled to an electrospray ionization-ion trap mass spectrometer. This technique provides information on the relative abundances of in idual glycans along with detailed structural information, including isomer differentiation and functional epitope characterization of N- and O-glycans obtained from minimal amounts of tissue down to a few thousand cells.
Publisher: Wiley
Date: 12-2008
Abstract: IgE-reactive proteins in raspberry (Rubus ideaus L.) were identified using PCR, RT-PCR, 2-DE and MS/MS peptide sequencing. Specific polyclonal antibodies and patient sera were used in Western blotting to identify crossreactive epitopes. Initially, two potential allergens Rub i 1 and Rub i 3 were detected using PCR, showing high sequence identity to proteins in Rosaceous species like Mal d 1 and Mal d 3 from apple, Pru av 1 and Pru av 3 from cherry and Pru p 1 and Pru p 3 from peach. Furthermore, de novo identified peptides of a protein band at about 30 kDa reacting with most of the patient sera tested (> 80%) revealed a high sequence homology with class III chitinases. Raspberry chitinase, when subjected to glycoproteomic analysis, showed typical complex plant-type N-glycans with a core alpha1,3 fucose and a beta1,2 xylose at least at one position, indicating the presence of crossreacting carbohydrate determinants (CCDs). Finally, MS/MS analysis revealed an IgE-reactive raspberry cyclophilin, homologous to Bet v 7. Results obtained suggest that the consumption of raspberries might be responsible for adverse reactions in sensitised in iduals.
Publisher: Public Library of Science (PLoS)
Date: 31-07-2007
Publisher: Elsevier BV
Date: 11-2022
Abstract: Recent evidence suggests that cancer cell-derived extracellular vesicles might facilitate immunoevasion. Glycans are known to play a key role in immunomodulation, especially when tethered to biological membranes. However, the extracellular vesicle glycocode in cancer immunoevasion remains a largely unexplored area with promising potential for new putative diagnostic and therapeutic applications.
Publisher: Elsevier BV
Date: 07-2006
Publisher: Oxford University Press (OUP)
Date: 11-2004
Abstract: Protein transport within cereal endosperm cells is complicated by the abundance of endoplasmic reticulum (ER)-derived and vacuolar protein bodies. For wheat storage proteins, two major transport routes run from the ER to the vacuole, one bypassing and one passing through the Golgi. Proteins traveling along each route converge at the vacuole and form aggregates. To determine the impact of this trafficking system on the fate of recombinant proteins expressed in wheat endosperm, we used confocal and electron microscopy to investigate the fate of three recombinant proteins containing different targeting information. KDEL-tagged recombinant human serum albumin, which is retrieved to the ER lumen in leaf cells, was deposited in prolamin aggregates within the vacuole of endosperm cells, most likely following the bulk of endogenous glutenins. Recombinant fungal phytase, a glycoprotein designed for secretion, was delivered to the same compartment, with no trace of the molecule in the apoplast. Glycan analysis revealed that this protein had passed through the Golgi. The localization of human serum albumin and phytase was compared to that of recombinant legumin, which contains structural targeting information directing it to the vacuole. Uniquely, legumin accumulated in the globulin inclusion bodies at the periphery of the prolamin bodies, suggesting a different mode of transport and/or aggregation. Our results demonstrate that recombinant proteins are deposited in an unexpected pattern within wheat endosperm cells, probably because of the unique storage properties of this tissue. Our data also confirm that recombinant proteins are invaluable tools for the analysis of protein trafficking in cereals.
Publisher: Frontiers Media SA
Date: 09-07-2018
Publisher: Elsevier BV
Date: 04-2010
Publisher: Wiley
Date: 10-2005
DOI: 10.1111/J.1742-4658.2005.04841.X
Abstract: Hyaluronidase (E.C. 3.2.1.35), one of the three major allergens of yellow jacket venom, is a glycoprotein of 45 kDa that is largely responsible for the cross-reactivity of wasp and bee venoms with sera of allergic patients. The asparagine-linked carbohydrate often appears to constitute the common IgE-binding determinant. Using a combination of MALDI MS and HPLC of 2-aminopyridine-labelled glycans, we found core-difucosylated paucimannosidic glycans to be the major species in the 43-45 kDa band of Vespula vulgaris and also in the corresponding bands of venoms from five other wasp species (V. germanica, V. maculifrons, V. pensylvanica, V. flavopilosa and V. squamosa). Concomitant peptide mapping of the V. vulgaris 43 kDa band identified the known hyaluronidase, Ves v 2 (SwissProt P49370), but only as a minor component. De novo sequencing by tandem MS revealed the predominating peptides to resemble a different, yet homologous, sequence. cDNA cloning retrieved a sequence with 58 and 59% homology to the previously known isoform and to the Dolichovespula maculata and Polistes annularis hyaluronidases. Close homologues of this new, putative hyaluronidase b (Ves v 2b) were also the major isoform in the other wasp venoms.
Publisher: American Chemical Society (ACS)
Date: 13-04-2010
DOI: 10.1021/AC901717N
Abstract: O-Linked glycosylation often occurs in mucin-type domains that are heavily and heterogeneously glycosylated and are challenging to analyze. The analysis of these domains is often overlooked because of these difficulties, but changes in mucinlike domain glycosylation are implicated in many diseases. Here we have explored several strategies to determine the heterogeneity of mucinlike O-glycosylated domains. Four glucanases secreted in large quantities from Trichoderma reesei, all containing heavily O-glycosylated mucinlike linker regions, were used as a model system. The strategies involved monosaccharide compositional analysis and identification of the released glycans by HPAEC-PAD and carbon-LC ESI-MS/MS. Glycosylated peptides were generated by different protease digestions (trypsin, papain, Asp-N, PreTAQ) and enriched by HILIC microcolumns, to determine the glycopeptide heterogeneity and glycosylation sites. The complex O-glycan heterogeneity on the intact glycoproteins and the enriched mucin-type domains was determined by MALDI-MS and ESI-MS, but the dense O-glycosylation in the mucin-type domains conferred high resistance to protease cleavage. ETD-MS/MS of the glycopeptide-enriched protease digests was unsuccessful for the de novo assignment of O-glycosylation at in idual sites within the mucin-type domains but allowed several previously unknown O-linked sites outside the defined linker region to be found on two of the four glucanases. The protease digests produced many glycopeptides as determined by CID-MS/MS, but ETD fragmentation of these resulted in only a few interpretable spectra, suggesting that the use of ETD for determining the heterogeneous O-glycosylation at specific sites in regions of multiple occupancy is still in its infancy.
Publisher: American Chemical Society (ACS)
Date: 21-12-2013
DOI: 10.1021/PR300693F
Abstract: Soluble amyloid precursor protein alpha (sAPPalpha) is a cleavage product of the amyloid precursor protein (APP), the etiologic agent in Alzheimer's disease (AD). Reduced expression of sAPPalpha was previously found in the brains of AD patients, and it was suggested that sAPPalpha might counteract neurotoxic effects of Abeta, another APP cleavage product with enhanced abundance in Alzheimer's diseased brains. However, little is known about the biological functions of sAPPalpha. Thus, efficient production of this protein is a prerequisite for further studies. The unicellular eukaryotic parasite Leishmania tarentolae has recently emerged as a promising expression system for eukaryotic proteins due to its ability to posttranslationally modify proteins combined with easy cultivation and high protein yield. Interestingly, sAPPalpha produced in L. tarentolae was biologically active and glycosylated. In contrast to nonglycosylated sAPPalpha expressed in Eschericha coli, it also featured higher stability against enzymatic degradation. Detailed analysis of the glycosylation pattern of sAPPalpha produced in L. tarentolae by PGC-LC-ESI-MS/MS N-glycan analysis identified among eukaryotic species the highly conserved core pentasaccharide (Man3GlcNAc2) as being attached to Asn467 of sAPPalpha. Using oxonium ion scanning of CID-MS/MS spectra in combination with ETD fragmentation, we also identified two peptides (peptides 269-288 and 575-587) modified with N-acetyl hexosamine (HexNAc) residues. One of these O-glycosylation sites could be unambiguously assigned to Thr576 of sAPPalpha. This is the first time that O-glycosylation of a recombinant protein expressed in L. tarentolae has been demonstrated. Together, human sAPPalpha produced in L. tarentolae was N- and O-glycosylated on similar sites as described for mammalian-expressed sAPPalpha and showed similar biological activity. This demonstrates that L. tarentolae is a very suitable and simple to handle expression system for mammalian glycoproteins.
Publisher: Springer Science and Business Media LLC
Date: 05-12-2000
Publisher: Wiley
Date: 16-10-2019
Abstract: While aberrant protein glycosylation is a recognized characteristic of human cancers, advances in glycoanalytics continue to discover new associations between glycoproteins and tumorigenesis. This glycomics-centric study investigates a possible link between protein paucimannosylation, an under-studied class of human N-glycosylation [Man
Publisher: American Chemical Society (ACS)
Date: 21-12-2018
DOI: 10.1021/ACS.JPROTEOME.8B00766
Abstract: Knowledge of glycoproteins, their site-specific glycosylation patterns, and the glycan structures that they present to their recognition partners in health and disease is gradually being built on using a range of experimental approaches. The data from these analyses are increasingly being standardized and presented in various sources, from supplemental tables in publications to localized servers in investigator laboratories. Bioinformatics tools are now needed to collect these data and enable the user to search, display, and connect glycomics and glycoproteomics to other sources of related proteomics, genomics, and interactomics information. We here introduce GlyConnect ( glyconnect.expasy.org/ ), the central platform of the Glycomics@ExPASy portal for glycoinformatics. GlyConnect has been developed to gather, monitor, integrate, and visualize data in a user-friendly way to facilitate the interpretation of collected glycoscience data. GlyConnect is designed to accommodate and integrate multiple data types as they are increasingly produced.
Publisher: Elsevier BV
Date: 09-2018
DOI: 10.1053/J.GASTRO.2018.05.030
Abstract: Biomarkers are needed for early detection of Crohn's disease (CD) and ulcerative colitis (UC) or to predict patient outcomes. Glycosylation is a common and complex posttranslational modification of proteins that affects their structure and activity. We compared plasma N-glycosylation profiles between patients with CD or UC and healthy in iduals (controls). We analyzed the total plasma N-glycomes of 2635 patients with inflammatory bowel diseases and 996 controls by mass spectrometry with a linkage-specific sialic acid derivatization technique. Plasma s les were acquired from 2 hospitals in Italy (discovery cohort, 1989 patients with inflammatory bowel disease [IBD] and 570 controls) and 1 medical center in the United States (validation cohort, 646 cases of IBD and 426 controls). Sixty-three glycoforms met our criteria for relative quantification and were extracted from the raw data with the software MassyTools. Common features shared by the glycan compositions were combined in 78 derived traits, including the number of antennae of complex-type glycans and levels of fucosylation, bisection, galactosylation, and sialylation. Associations of plasma N-glycomes with age, sex, CD, UC, and IBD-related parameters such as disease location, surgery and medication, level of C-reactive protein, and sedimentation rate were tested by linear and logistic regression. Plasma s les from patients with IBD had a higher abundance of large-size glycans compared with controls, a decreased relative abundance of hybrid and high-mannose structures, lower fucosylation, lower galactosylation, and higher sialylation (α2,3- and α2,6-linked). We could discriminate plasma from patients with CD from that of patients with UC based on higher bisection, lower galactosylation, and higher sialylation (α2,3-linked). Glycosylation patterns were associated with disease location and progression, the need for a more potent medication, and surgery. These results were replicated in a large independent cohort. We performed high-throughput analysis to compare total plasma N-glycomes of in iduals with vs without IBD and to identify patterns associated with disease features and the need for treatment. These profiles might be used in diagnosis and for predicting patients' responses to treatment.
Publisher: Springer Science and Business Media LLC
Date: 11-2006
DOI: 10.1007/S10719-006-7633-Z
Abstract: Chondroitin and heparan sulphates have key functions in animal development and their synthesis is initiated by the action of UDP-alpha-D-xylose:proteoglycan core protein beta-D-xylosyltransferase (EC 2.4.2.26). cDNAs encoding this enzyme have been previously cloned from mammalian species this in turn facilitated identification of corresponding Caenorhabditis elegans (sqv-6) and Drosophila melanogaster (oxt) genes. In the present study, we report the expression in Pichia pastoris and subsequent assay using either MALDI-TOF MS or RP-HPLC of recombinant forms of the Caenorhabditis xylosyltransferase SQV-6 and the human xylosyltransferase I, in addition to extending our previous studies on the xylosyltransferase from Drosophila. The enzyme activities were tested with a number of peptide substrates based on portions of the human bikunin, human perlecan and Drosophila syndecan core peptides. Whereas a variant of the latter, containing two Ser-Gly motifs was only modified on one of these motifs, the perlecan peptide with three Ser-Gly motifs could be multiply modified in vitro. Using this substrate, we could for the first time follow, by mass spectrometry, the xylosylation of a peptide with multiple xylosyltransferase acceptor motifs.
Publisher: Wiley
Date: 15-10-2010
DOI: 10.1111/J.1423-0410.2010.01415.X
Abstract: A human plasma-derived butyrylcholinesterase preparation manufactured on the industrial scale is described. The human butyrylcholinesterase (hBChE) product was extensively investigated for its purity using immunological and electrophoretic methods and characterized by thorough glycoproteomic approaches. A comprehensive preclinical testing programme addressing safety and pharmacokinetic parameters supplemented the biochemical characterization. The high-purity hBChE preparation is tetrameric and has high specific activity and molecular integrity of the protein backbone. Acute toxicity studies and in vivo thrombogenicity studies provided evidence of a sufficient safety margin for use in humans. Extensive preclinical safety and pharmacokinetic testing confirmed that this hBChE preparation can be used for further efficacy testing as a bioscavenger for toxic organophosphate compounds in appropriate animal models and ultimately in humans.
Publisher: Springer Science and Business Media LLC
Date: 13-05-2016
Publisher: Portland Press Ltd.
Date: 20-07-2021
DOI: 10.1042/BST20200879
Abstract: Protein glycosylation is one of the most common post-translational modifications that are essential for cell function across all domains of life. Changes in glycosylation are considered a hallmark of many diseases, thus making glycoproteins important diagnostic and prognostic biomarker candidates and therapeutic targets. Glycoproteomics, the study of glycans and their carrier proteins in a system-wide context, is becoming a powerful tool in glycobiology that enables the functional analysis of protein glycosylation. This ‘Hitchhiker's guide to glycoproteomics’ is intended as a starting point for anyone who wants to explore the emerging world of glycoproteomics. The review moves from the techniques that have been developed for the characterisation of single glycoproteins to technologies that may be used for a successful complex glycoproteome characterisation. Ex les of the variety of approaches, methodologies, and technologies currently used in the field are given. This review introduces the common strategies to capture glycoprotein-specific and system-wide glycoproteome data from tissues, body fluids, or cells, and a perspective on how integration into a multi-omics workflow enables a deep identification and characterisation of glycoproteins — a class of biomolecules essential in regulating cell function.
Publisher: Mary Ann Liebert Inc
Date: 08-2010
Abstract: One common method used for analyzing the glycoproteome is chromatography using multiple lectins that display different affinities toward oligosaccharide structures. Much has been done to determine lectin affinity using standard glycoproteins with known glycosylation however, a knowledge of the selectivity and specificity of lectins exposed to complex mixtures of proteins is required if they are to be used as a means of studying the glycoproteome. In the present study, three lectins (Concanavalin A, Jacalin, and Wheat Germ Agglutinin) were used to fractionate glycoproteins from two different complex environments: (1) cell membranes and (2) plasma. Reproducible enrichment of glycoproteins from these s les has been shown to result from the combined use of these lectins. However, the global glycan profiles of the released N- and O-linked oligosaccharides from the glycoproteins retained by the lectins, and from those glycoproteins that did not bind, using both these complex s les, were found to be very similar. That is, although the lectins selectively and reproducibly retained some glycoproteins, other proteins with the same attached oligosaccharide structures did not bind. Some small N- and O-glycan differences were observed in the bound fractions but there was little absolute specificity toward in idual oligosaccharide structures known to have high affinity to these lectins. These data indicate that lectins are useful for fractionating glycoproteins from complex mixtures, but that the overall glycoproteome is not isolated by this approach.
Location: Austria
Start Date: 2022
End Date: 2023
Funder: Australian Research Council
View Funded ActivityStart Date: 2022
End Date: 2023
Funder: Australian Research Council
View Funded ActivityStart Date: 2016
End Date: 2022
Funder: Crohn's and Colitis Foundation
View Funded ActivityStart Date: 2007
End Date: 2008
Funder: FWF Austrian Science Fund
View Funded ActivityStart Date: 2016
End Date: 2020
Funder: Fundação para a Ciência e Tecnologia
View Funded ActivityStart Date: 2016
End Date: 2019
Funder: Fundação para a Ciência e Tecnologia
View Funded ActivityStart Date: 2018
End Date: 2019
Funder: Australian Research Council
View Funded ActivityStart Date: 2017
End Date: 2021
Funder: Australian Research Council
View Funded ActivityStart Date: 2014
End Date: 2020
Funder: Australian Research Council
View Funded ActivityStart Date: 01-2018
End Date: 12-2019
Amount: $270,427.00
Funder: Australian Research Council
View Funded ActivityStart Date: 04-2022
End Date: 12-2023
Amount: $727,596.00
Funder: Australian Research Council
View Funded ActivityStart Date: 10-2014
End Date: 12-2020
Amount: $23,000,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 01-2017
End Date: 01-2021
Amount: $805,168.00
Funder: Australian Research Council
View Funded ActivityStart Date: 06-2022
End Date: 05-2023
Amount: $630,880.00
Funder: Australian Research Council
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