Environmental polarity induces conformational transitions in a helical peptide sequence from bacteriophage T4 lysozyme and its tandem duplicate: a molecular dynamics simulation study

Verfasser / Beitragende:
[Harpreet Kaur, Yellamraju Sasidhar]
Ort, Verlag, Jahr:
2015
Enthalten in:
Journal of Molecular Modeling, 21/4(2015-04-01), 1-14
Format:
Artikel (online)
ID: 605512639
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024 7 0 |a 10.1007/s00894-015-2621-5  |2 doi 
035 |a (NATIONALLICENCE)springer-10.1007/s00894-015-2621-5 
245 0 0 |a Environmental polarity induces conformational transitions in a helical peptide sequence from bacteriophage T4 lysozyme and its tandem duplicate: a molecular dynamics simulation study  |h [Elektronische Daten]  |c [Harpreet Kaur, Yellamraju Sasidhar] 
520 3 |a Our recent molecular dynamics (MD) simulation of an insertion/duplication mutant ‘L20' of bacteriophage T4 lysozyme demonstrated a solvent induced α→β transition in a loosely held duplicate helical region, while α-helical conformation in the parent region was relatively stabilized by its tertiary interactions with the neighboring residues. The solution NMR of the parent helical sequence, sans its protein context, showed no inherent tendency to adopt a particular secondary structure in pure water but showed α-helical propensity in TFE/water and SDS micelles. In this study we investigate the conformational preference of the ‘parent' and ‘duplicate' sequences, sans the protein context, in pure water and an apolar TFE/water solution. Apolar TFE/water solution is a model for non-polar protein context. We performed MD simulations of the two peptides, in explicit water and 80% (v/v) TFE/water, using GROMOS 53a6 force field, at 300K and 1bar (under NPT conditions). We show that in TFE/water mixture, salt bridges are stabilized by apolar TFE molecules and main chain-main chain hydrogen bonds promote the α-helical conformation, particularly in the duplicate peptide. Solvent exposure, in pure water, resulted in an α→β transition to form a triple stranded β-sheet structure in the ‘duplicate' sequence, with a rare psi-loop topology, while a mixture of turn/bend conformations were adopted by the ‘parent' sequence. Thus the differences in conformational preference of the parent and duplicate sequence sans protein context, in pure water and TFE/water, implicate the importance of the environment polarity in dictating the peptide conformation. Mechanism of folding of the observed psi-loop in the duplicate sequence gives insights into folding of this rare β-sheet topology. Graphical Abstract An apolar environment provided by TFE protects the salt bridges and main chain-main chain hydrogen bonds from solvent exposure in the duplicate peptide sequence, from bacteriophage T4 lysozyme mutant 'L20'. This results in retention of residual a-helical propensity (top). Exposure to pure water results in an a®b transition resulting in a triple stranded b-hairpin (bottom). Differences in conformational preference of the peptide sequence upon change in solvent conditions implicate the importance of the environmental polarity in dictating the peptide conformation 
540 |a Springer-Verlag Berlin Heidelberg, 2015 
690 7 |a α→β transition  |2 nationallicence 
690 7 |a Bacteriophage T4 lysozyme  |2 nationallicence 
690 7 |a Salt bridges  |2 nationallicence 
690 7 |a Solvent shielding  |2 nationallicence 
690 7 |a TFE  |2 nationallicence 
690 7 |a Triple stranded β-hairpin  |2 nationallicence 
700 1 |a Kaur  |D Harpreet  |u Department of Chemistry, Indian Institute of Technology Bombay, 400076, Powai, Mumbai, India  |4 aut 
700 1 |a Sasidhar  |D Yellamraju  |u Department of Chemistry, Indian Institute of Technology Bombay, 400076, Powai, Mumbai, India  |4 aut 
773 0 |t Journal of Molecular Modeling  |d Springer Berlin Heidelberg  |g 21/4(2015-04-01), 1-14  |x 1610-2940  |q 21:4<1  |1 2015  |2 21  |o 894 
856 4 0 |u https://doi.org/10.1007/s00894-015-2621-5  |q text/html  |z Onlinezugriff via DOI 
898 |a BK010053  |b XK010053  |c XK010000 
900 7 |a Metadata rights reserved  |b Springer special CC-BY-NC licence  |2 nationallicence 
908 |D 1  |a research-article  |2 jats 
949 |B NATIONALLICENCE  |F NATIONALLICENCE  |b NL-springer 
950 |B NATIONALLICENCE  |P 856  |E 40  |u https://doi.org/10.1007/s00894-015-2621-5  |q text/html  |z Onlinezugriff via DOI 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Kaur  |D Harpreet  |u Department of Chemistry, Indian Institute of Technology Bombay, 400076, Powai, Mumbai, India  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Sasidhar  |D Yellamraju  |u Department of Chemistry, Indian Institute of Technology Bombay, 400076, Powai, Mumbai, India  |4 aut 
950 |B NATIONALLICENCE  |P 773  |E 0-  |t Journal of Molecular Modeling  |d Springer Berlin Heidelberg  |g 21/4(2015-04-01), 1-14  |x 1610-2940  |q 21:4<1  |1 2015  |2 21  |o 894