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The sequence TGAAKAVALVL from glyceraldehyde-3-phosphate dehydrogenase displays structural ambivalence and interconverts between alpha-helical and beta-hairpin conformations mediated by collapsed conformational states

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Title The sequence TGAAKAVALVL from glyceraldehyde-3-phosphate dehydrogenase displays structural ambivalence and interconverts between alpha-helical and beta-hairpin conformations mediated by collapsed conformational states
 
Creator PATEL, S
BALAJI, PV
SASIDHAR, YU
 
Subject molecular-dynamics simulations
polyproline ii helix
particle mesh ewald
transition mechanism
secondary structure
sheet protein
peptide
water
fragments
lactoglobulin
helix to hairpin transition
bend
turn
peptide model
structural ambivalence
gromacs
protein folding
molecular dynamics
 
Description The peptide TGAAKAVALVL from glyceraldehyde-3-phosphate dehydrogenase adopts a helical conformation in the crystal structure and is a site for two hydrated helical segments, which are thought to be helical folding intermediates. Overlapping sequences of four to five residues from the peptide, sample both helical and strand conformations in known protein structures, which are dissimilar to glyceraldehyde-3-phosphate dehydrogenase suggesting that the peptide may have a structural ambivalence. Molecular dynamics simulations of the peptide sequence performed for a total simulation time of 1.2 Ps. starting from the various initial conformations using GROMOS96 force field under NVT conditions, show that the peptide samples a large number of conformational forms with transitions from alpha-helix to beta-hairpin and vice versa. The peptide, therefore, displays a structural ambivalence. The mechanism from alpha-helix to beta-hair-pin transition and vice versa reveals that the compact bends and turns conformational forms mediate such conformational transitions. These compact structures including helices and hairpins have similar hydrophobic radius of gyration (R-gh) values suggesting that similar hydrophobic interactions govem these conformational forms. The distribution of conformational energies is Gaussian with helix sampling lowest energy followed by the hairpins and coil. The lowest potential energy of the full helix may enable the peptide to take up helical conformation in the crystal structure of the glyceraldehyde-3-phosphate dehydrogenase, even though the peptide has a preference for hairpin too. The relevance of folding and unfolding events observed in our simulations to hydrophobic collapse model of protein folding are discussed. Copyright (C) 2007 European Peptide Society and , Ltd.
 
Publisher JOHN WILEY & SONS LTD
 
Date 2011-08-17T01:25:51Z
2011-12-26T12:55:15Z
2011-12-27T05:43:59Z
2011-08-17T01:25:51Z
2011-12-26T12:55:15Z
2011-12-27T05:43:59Z
2007
 
Type Article
 
Identifier JOURNAL OF PEPTIDE SCIENCE, 13(5), 314-326
1075-2617
http://dx.doi.org/10.1002/psc.843
http://dspace.library.iitb.ac.in/xmlui/handle/10054/9693
http://hdl.handle.net/10054/9693
 
Language en