ORCID Profile
0000-0002-0267-2631
Current Organisation
Universidade Federal de São Paulo
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Publisher: Elsevier BV
Date: 07-2017
Publisher: American Chemical Society (ACS)
Date: 03-06-2015
DOI: 10.1021/ACS.JNATPROD.5B00166
Abstract: Chemical investigations of the ethanolic extracts from the flowers and leaves of Hymenaea stigonocarpa Mart. ex Hayne afforded one new ent-halimane diterpenoid, 18-hydroxy-ent-halima-1(10),13-(E)-dien-15-oic acid (1), together with five known compounds (2-6). The structural elucidation was performed by means of NMR (COSY, HSQC, HMBC, and NOESY) and MS analyses. Complete (1)H and (13)C NMR data assignments are also reported for labd-13-en-8β-ol-15-oic (2) and labd-7,13-dien-15-oic (3) acids. The absolute configurations of 1 and 2 were established by comparison of experimental and calculated Raman optical activity spectra.
Publisher: Wiley
Date: 05-07-2014
DOI: 10.1002/CHIR.22351
Abstract: Recent Raman and Raman optical activity (ROA) results have demonstrated that dimethyl sulfoxide (DMSO) induces the selective conversion of α-helix motifs into the poly(L-proline) II (PPII) helix conformation in an array of proteins, while β-sheets remain mostly unaffected. Human serum albumin (HSA), a highly α-helical protein, underwent the most dramatic changes and, therefore, was selected as a model for further investigations into the mechanism of this conformational change. Herein we report the use of two-dimensional ROA correlation analysis applying synchronous, autocorrelation, and moving windows approaches in order to understand the conformational transitions in HSA as a function of DMSO concentration. Our results indicate that the destabilization of native α-helix starts at DMSO concentrations as little as 20% in water (v/v), with the transition to PPII helix being complete at ~80% DMSO. These results clearly indicate that any protein preparation containing relatively low concentrations of DMSO should consider possible disruptions in α-helical domains.
Publisher: Informa UK Limited
Date: 02-01-2016
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3CP53525H
Abstract: The function of a protein is determined by its structure, which is intrinsically related to its solvent environment. Based on this paradigm, there has been a great deal of interest in the role that non-aqueous solvents play in regulating protein structure, with some debate in the literature regarding dimethyl sulfoxide (DMSO). Thus, in this work we have used Raman and Raman optical activity (ROA) spectroscopies to investigate conclusively the changes induced by DMSO in the secondary structure of an array of proteins including human serum albumin (highly α-helical), bovine α-lactalbumin (mainly α-helical), bovine ribonuclease A (containing both α-helix and β-sheet), bovine β-lactoglobulin (mainly β-sheet), and bovine α-casein (disordered). Our results clearly demonstrate that 100% DMSO solutions destabilize α-helices completely, converting them into the poly(L-proline) II (PPII) helix conformation. However, low concentrations of DMSO (10% v/v) were found to have little effect on the structure of even the most helical protein, human serum albumin. In the case of α-casein, the natively unfolded protein rich in PPII helix was converted into a further disordered structure when dissolved in pure DMSO. By contrast, β-sheets remained mostly unaffected regardless of DMSO concentration. While providing new insights into protein structure in organic solvents, this work reinforces the capability of vibrational optical activity to assess conformations of biomolecules in conditions not accessible to other techniques, such as X-ray crystallography and NMR.
Publisher: Elsevier BV
Date: 10-2015
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5NP00027K
Abstract: A comprehensive look into application of vibrational optical activity methods for conformational and configurational assignments in natural product molecules over the last 15 years is provided.
Publisher: American Chemical Society (ACS)
Date: 20-02-2015
DOI: 10.1021/NP5007668
Abstract: A new orbitide named ribifolin was isolated and characterized from Jatropha ribifolia using mass spectrometry, NMR spectroscopy, quantitative amino acid analysis, molecular dynamics/simulated annealing, and Raman optical activity measurements and calculations. Ribifolin (1) and its linear form (1a) were synthesized by solid-phase peptide synthesis, followed by evaluation of its antiplasmodial and cytotoxicity activities. Compound 1 was moderately effective (IC50 = 42 μM) against the Plasmodium falciparum strain 3D7.
Location: Brazil
No related grants have been discovered for João Marcos Batista Junior.