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Theoretical study for volume changes associated with the helix–coil transition of peptides
Author(s) -
Imai Takashi,
Harano Yuichi,
Kovalenko Andriy,
Hirata Fumio
Publication year - 2001
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/1097-0282(200112)59:7<512::aid-bip1056>3.0.co;2-c
Subject(s) - chemistry , van der waals force , peptide , volume (thermodynamics) , thermodynamics , oligomer , glycine , crystallography , helix (gastropod) , amino acid , organic chemistry , molecule , biochemistry , physics , ecology , biology , snail
Abstract We calculate the partial molar volumes and their changes associated with the coil(extended)‐to‐helix transition of two types of peptide, glycine–oligomer and glutamic acid–oligomer, in aqueous solutions by using the Kirkwood–Buff solution theory coupled with the three‐dimensional reference interaction site model (3D‐RISM) theory. The volume changes associated with the transition are small and positive. The volume is analyzed by decomposing it into five contributions following the procedure proposed by Chalikian and Breslauer: the ideal volume, the van der Waals volume, the void volume, the thermal volume, and the interaction volume. The ideal volumes and the van der Waals volumes do not change appreciably upon the transition. In the both cases of glycine–peptide and glutamic acid–peptide, the changes in the void volumes are positive, while those in the thermal volumes are negative, and tend to balance those in the void volumes. The change in the interaction volume of glycine‐peptide does not significantly contribute, while that of glutamic acid–peptide makes a negative contribution. © 2001 John Wiley & Sons, Inc. Biopolymers 59: 512–519, 2001