ORCID Profile
0000-0002-9573-1724
Current Organisation
Technische Universiteit Delft
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Publisher: American Association for the Advancement of Science (AAAS)
Date: 07-04-2017
Abstract: To repel infection by phage and mobile genetic elements, prokaryotes have a form of adaptive immune response and memory invested in clustered regularly interspaced short palindromic repeats and associated proteins (CRISPR-Cas). This molecular machinery can recognize and remember foreign nucleic acids by capturing and retaining small nucleotide sequences. On subsequent encounters, the cognate CRISPR-Cas marshals enzymatic defenses to destroy infecting elements that contain the same sequences. Jackson et al. review the molecular mechanisms by which erse CRISPR-Cas systems adapt and anticipate novel threats and evasive countermeasures from mobile genetic elements. Science , this issue p. eaal5056
Publisher: Informa UK Limited
Date: 14-03-2013
DOI: 10.4161/RNA.24046
Publisher: American Society for Microbiology
Date: 04-2006
DOI: 10.1128/JB.188.7.2392-2399.2006
Abstract: Sulfolobus solfataricus is an aerobic crenarchaeon that thrives in acidic volcanic pools. In this study, we have purified and characterized a thermostable α-galactosidase from cell extracts of S. solfataricus P2 grown on the trisaccharide raffinose. The enzyme, designated GalS, is highly specific for α-linked galactosides, which are optimally hydrolyzed at pH 5 and 90°C. The protein consists of 74.7-kDa subunits and has been identified as the gene product of open reading frame Sso3127. Its primary sequence is most related to plant enzymes of glycoside hydrolase family 36, which are involved in the synthesis and degradation of raffinose and stachyose. Both the galS gene from S. solfataricus P2 and an orthologous gene from Sulfolobus tokodaii have been cloned and functionally expressed in Escherichia coli , and their activity was confirmed. At present, these Sulfolobus enzymes not only constitute a distinct type of thermostable α-galactosidases within glycoside hydrolase clan D but also represent the first members from the Archaea .
Publisher: Elsevier
Date: 2006
Publisher: Proceedings of the National Academy of Sciences
Date: 07-04-2014
Abstract: Bacteria are constantly exposed to foreign elements, such as bacteriophages and plasmids. The CRISPR-Cas (clustered regularly interspaced short palindromic repeats–CRISPR associated) adaptive immune systems provide heritable sequence-specific protection against these invaders. To develop immunity, bacteria add segments of foreign nucleic acid to their CRISPR memory. However, phage and plasmid mutants can evade CRISPR-Cas recognition by altering their targeted sequence. CRISPR-Cas responds to evasion by quickly generating immunity by acquiring new pieces of invader genome. We determined that this rapid generation of resistance is promiscuous, with recognition of highly erged or related elements eliciting new immunity. Our results demonstrate that CRISPR-Cas systems are more robust than previously thought and, not only have a highly specific resistance memory, but also have a broad ability to identify ergent genetic elements.
Publisher: Elsevier BV
Date: 09-2006
Publisher: Springer Science and Business Media LLC
Date: 03-10-2016
DOI: 10.1038/NCOMMS12853
Abstract: CRISPR–Cas systems provide bacteria with adaptive immunity against foreign nucleic acids by acquiring short, invader-derived sequences called spacers. Here, we use high-throughput sequencing to analyse millions of spacer acquisition events in wild-type populations of Pectobacterium atrosepticum . Plasmids not previously encountered, or plasmids that had escaped CRISPR–Cas targeting via point mutation, are used to provoke naive or primed spacer acquisition, respectively. The origin, location and order of spacer acquisition show that spacer selection through priming initiates near the site of CRISPR–Cas recognition (the protospacer), but on the displaced strand, and is consistent with 3′–5′ translocation of the Cas1:Cas2-3 acquisition machinery. Newly acquired spacers determine the location and strand specificity of subsequent spacers and demonstrate that interference-driven spacer acquisition (‘targeted acquisition’) is a major contributor to adaptation in type I-F CRISPR–Cas systems. Finally, we show that acquisition of self-targeting spacers is occurring at a constant rate in wild-type cells and can be triggered by foreign DNA with similarity to the bacterial chromosome.
Publisher: Cold Spring Harbor Laboratory
Date: 31-08-2023
DOI: 10.1101/2023.08.30.555055
Abstract: Bottom-up mass spectrometry-based proteomics is challenged by the task of identifying the peptide that generates a tandem mass spectrum. Traditional methods that rely on known peptide sequence databases are limited and may not be applicable in certain contexts. De novo peptide sequencing, which assigns peptide sequences to the spectra without prior information, is valuable for various biological applications yet, due to a lack of accuracy, it remains challenging to apply this approach in many situations. Here, we introduce InstaNovo, a transformer neural network with the ability to translate fragment ion peaks into the sequence of amino acids that make up the studied peptide(s). The model was trained on 28 million labelled spectra matched to ~742k human peptides from the ProteomeTools project. We demonstrate that InstaNovo outperforms current state-of-the-art methods on benchmark datasets and showcase its utility in several applications. Building upon human intuition, we also introduce InstaNovo+, a multinomial diffusion model that further improves performance by iterative refinement of predicted sequences. Using these models, we could de novo sequence antibody-based therapeutics with unprecedented coverage, discover novel peptides, and detect unreported organisms in different datasets, thereby expanding the scope and detection rate of proteomics searches. Finally, we could experimentally validate tryptic and non-tryptic peptides with targeted proteomics, demonstrating the fidelity of our predictions. Our models unlock a plethora of opportunities across different scientific domains, such as direct protein sequencing, immunopeptidomics, and exploration of the dark proteome.
Publisher: Wiley
Date: 03-2006
Abstract: In the last decade, an increasing number of sequenced archaeal genomes have become available, opening up the possibility for functional genomic analyses. Here, we reconstructed the central carbon metabolism in the hyperthermophilic crenarchaeon Sulfolobus solfataricus (glycolysis, gluconeogenesis and tricarboxylic acid cycle) on the basis of genomic, proteomic, transcriptomic and biochemical data. A 2-DE reference map of S. solfataricus grown on glucose, consisting of 325 unique ORFs in 255 protein spots, was created to facilitate this study. The map was then used for a differential expression study based on (15)N metabolic labelling (yeast extract + tryptone-grown cells (YT) vs. glucose-grown cells (G)). In addition, the expression ratio of the genes involved in carbon metabolism was studied using DNA microarrays. Surprisingly, only 3 and 14% of the genes and proteins, respectively, involved in central carbon metabolism showed a greater than two-fold change in expression level. All results are discussed in the light of the current understanding of central carbon metabolism in S. solfataricus and will help to obtain a system-wide understanding of this organism.
Publisher: Portland Press Ltd.
Date: 07-08-2014
DOI: 10.1042/BJ20131474
Abstract: MBF1 (multi-protein bridging factor 1) is a protein containing a conserved HTH (helix–turn–helix) domain in both eukaryotes and archaea. Eukaryotic MBF1 has been reported to function as a transcriptional co-activator that physically bridges transcription regulators with the core transcription initiation machinery of RNA polymerase II. In addition, MBF1 has been found to be associated with polyadenylated mRNA in yeast as well as in mammalian cells. aMBF1 (archaeal MBF1) is very well conserved among most archaeal lineages however, its function has so far remained elusive. To address this, we have conducted a molecular characterization of this aMBF1. Affinity purification of interacting proteins indicates that aMBF1 binds to ribosomal subunits. On sucrose density gradients, aMBF1 co-fractionates with free 30S ribosomal subunits as well as with 70S ribosomes engaged in translation. Binding of aMBF1 to ribosomes does not inhibit translation. Using NMR spectroscopy, we show that aMBF1 contains a long intrinsically disordered linker connecting the predicted N-terminal zinc-ribbon domain with the C-terminal HTH domain. The HTH domain, which is conserved in all archaeal and eukaryotic MBF1 homologues, is directly involved in the association of aMBF1 with ribosomes. The disordered linker of the ribosome-bound aMBF1 provides the N-terminal domain with high flexibility in the aMBF1–ribosome complex. Overall, our findings suggest a role for aMBF1 in the archaeal translation process.
Publisher: Oxford University Press (OUP)
Date: 27-10-2023
DOI: 10.1093/NAR/GKAD890
Publisher: Cold Spring Harbor Laboratory
Date: 26-01-2019
DOI: 10.1101/527796
Abstract: Microbiomes are vast communities of microbes and viruses that populate all natural ecosystems. Viruses have been considered the most variable component of microbiomes, as supported by virome surveys and ex les of high genomic mosaicism. However, recent evidence suggests that the human gut virome is remarkably stable compared to other environments. Here we investigate the origin, evolution, and epidemiology of crAssphage, a widespread human gut virus. Through a global collaboratory, we obtained DNA sequences of crAssphage from over one-third of the world's countries, and showed that its phylogeography is locally clustered within countries, cities, and in iduals. We also found colinear crAssphage-like genomes in both Old-World and New-World primates, challenging genomic mosaicism and suggesting that the association of crAssphage with primates may be millions of years old. We conclude that crAssphage is a benign globetrotter virus that may have co-evolved with the human lineage and an integral part of the normal human gut virome.
Publisher: Informa UK Limited
Date: 27-03-2013
DOI: 10.4161/RNA.24202
Publisher: Elsevier BV
Date: 05-2023
DOI: 10.1016/J.TIBTECH.2022.08.008
Abstract: In recent years, bacteriophage research has been boosted by a rising interest in using phage therapy to treat antibiotic-resistant bacterial infections. In addition, there is a desire to use phages and their unique proteins for specific biocontrol applications and diagnostics. However, the ability to manipulate phage genomes to understand and control gene functions, or alter phage properties such as host range, has remained challenging due to a lack of universal selectable markers. Here, we discuss the state-of-the-art techniques to engineer and select desired phage genomes using advances in cell-free methodologies and clustered regularly interspaced short palindromic repeats-CRISPR associated protein (CRISPR-Cas) counter-selection approaches.
No related grants have been discovered for Stan Brouns.