Unfolding of α-helical 20-residue poly-glutamic acid analyzed by multiple runs of canonical molecular dynamics simulations
Elucidating the molecular mechanism of helix–coil transitions of short peptides is a long-standing conundrum in physical chemistry. Although the helix–coil transitions of poly-glutamic acid (PGA) have been extensively studied, the molecular details of its unfolding process still remain unclear. We p...
Main Authors: | , , , |
---|---|
Format: | Article |
Language: | English |
Published: |
PeerJ Inc.
2018-05-01
|
Series: | PeerJ |
Subjects: | |
Online Access: | https://peerj.com/articles/4769.pdf |
id |
doaj-86b1a568c5694e638fdb349fd864d770 |
---|---|
record_format |
Article |
spelling |
doaj-86b1a568c5694e638fdb349fd864d7702020-11-25T00:08:13ZengPeerJ Inc.PeerJ2167-83592018-05-016e476910.7717/peerj.4769Unfolding of α-helical 20-residue poly-glutamic acid analyzed by multiple runs of canonical molecular dynamics simulationsNaoki Ogasawara0Kota Kasahara1Ryosuke Iwai2Takuya Takahashi3Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, JapanCollege of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, JapanGraduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, JapanCollege of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, JapanElucidating the molecular mechanism of helix–coil transitions of short peptides is a long-standing conundrum in physical chemistry. Although the helix–coil transitions of poly-glutamic acid (PGA) have been extensively studied, the molecular details of its unfolding process still remain unclear. We performed all-atom canonical molecular dynamics simulations for a 20-residue PGA, over a total of 19 μs, in order to investigate its helix-unfolding processes in atomic resolution. Among the 28 simulations, starting with the α-helical conformation, all showed an unfolding process triggered by the unwinding of terminal residues, rather than by kinking and unwinding of the middle region of the chain. The helix–coil–helix conformation which is speculated by the previous experiments was not observed. Upon comparison between the N- and C-termini, the latter tended to be unstable and easily unfolded. While the probabilities of helix elongation were almost the same among the N-terminal, middle, and C-terminal regions of the chain, unwinding of the helix was enriched at the C-terminal region. The turn and 310-helix conformations were kinetic intermediates in the formation and deformation of α-helix, consistent with the previous computational studies for Ala-based peptides.https://peerj.com/articles/4769.pdfMolecular dynamicsMolecular simulationPoly-glutamic acidConformational changePeptide denaturationHelix unfolding |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Naoki Ogasawara Kota Kasahara Ryosuke Iwai Takuya Takahashi |
spellingShingle |
Naoki Ogasawara Kota Kasahara Ryosuke Iwai Takuya Takahashi Unfolding of α-helical 20-residue poly-glutamic acid analyzed by multiple runs of canonical molecular dynamics simulations PeerJ Molecular dynamics Molecular simulation Poly-glutamic acid Conformational change Peptide denaturation Helix unfolding |
author_facet |
Naoki Ogasawara Kota Kasahara Ryosuke Iwai Takuya Takahashi |
author_sort |
Naoki Ogasawara |
title |
Unfolding of α-helical 20-residue poly-glutamic acid analyzed by multiple runs of canonical molecular dynamics simulations |
title_short |
Unfolding of α-helical 20-residue poly-glutamic acid analyzed by multiple runs of canonical molecular dynamics simulations |
title_full |
Unfolding of α-helical 20-residue poly-glutamic acid analyzed by multiple runs of canonical molecular dynamics simulations |
title_fullStr |
Unfolding of α-helical 20-residue poly-glutamic acid analyzed by multiple runs of canonical molecular dynamics simulations |
title_full_unstemmed |
Unfolding of α-helical 20-residue poly-glutamic acid analyzed by multiple runs of canonical molecular dynamics simulations |
title_sort |
unfolding of α-helical 20-residue poly-glutamic acid analyzed by multiple runs of canonical molecular dynamics simulations |
publisher |
PeerJ Inc. |
series |
PeerJ |
issn |
2167-8359 |
publishDate |
2018-05-01 |
description |
Elucidating the molecular mechanism of helix–coil transitions of short peptides is a long-standing conundrum in physical chemistry. Although the helix–coil transitions of poly-glutamic acid (PGA) have been extensively studied, the molecular details of its unfolding process still remain unclear. We performed all-atom canonical molecular dynamics simulations for a 20-residue PGA, over a total of 19 μs, in order to investigate its helix-unfolding processes in atomic resolution. Among the 28 simulations, starting with the α-helical conformation, all showed an unfolding process triggered by the unwinding of terminal residues, rather than by kinking and unwinding of the middle region of the chain. The helix–coil–helix conformation which is speculated by the previous experiments was not observed. Upon comparison between the N- and C-termini, the latter tended to be unstable and easily unfolded. While the probabilities of helix elongation were almost the same among the N-terminal, middle, and C-terminal regions of the chain, unwinding of the helix was enriched at the C-terminal region. The turn and 310-helix conformations were kinetic intermediates in the formation and deformation of α-helix, consistent with the previous computational studies for Ala-based peptides. |
topic |
Molecular dynamics Molecular simulation Poly-glutamic acid Conformational change Peptide denaturation Helix unfolding |
url |
https://peerj.com/articles/4769.pdf |
work_keys_str_mv |
AT naokiogasawara unfoldingofahelical20residuepolyglutamicacidanalyzedbymultiplerunsofcanonicalmoleculardynamicssimulations AT kotakasahara unfoldingofahelical20residuepolyglutamicacidanalyzedbymultiplerunsofcanonicalmoleculardynamicssimulations AT ryosukeiwai unfoldingofahelical20residuepolyglutamicacidanalyzedbymultiplerunsofcanonicalmoleculardynamicssimulations AT takuyatakahashi unfoldingofahelical20residuepolyglutamicacidanalyzedbymultiplerunsofcanonicalmoleculardynamicssimulations |
_version_ |
1725416097378729984 |