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Theoretical study of the partial molar volume change associated with the pressure‐induced structural transition of ubiquitin
Author(s) -
Imai Takashi,
Ohyama Shusaku,
Kovalenko Andriy,
Hirata Fumio
Publication year - 2007
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1110/ps.072909007
Subject(s) - partial molar property , chemistry , thermodynamics , solvation , penetration (warfare) , volume (thermodynamics) , molecule , structural change , molar volume , molecular dynamics , denaturation (fissile materials) , chemical physics , computational chemistry , aqueous solution , organic chemistry , nuclear chemistry , engineering , economics , physics , macroeconomics , operations research
The partial molar volume (PMV) change associated with the pressure‐induced structural transition of ubiquitin is analyzed by the three‐dimensional reference interaction site model (3D‐RISM) theory of molecular solvation. The theory predicts that the PMV decreases upon the structural transition, which is consistent with the experimental observation. The volume decomposition analysis demonstrates that the PMV reduction is primarily caused by the decrease in the volume of structural voids in the protein, which is partially canceled by the volume expansion due to the hydration effects. It is found from further analysis that the PMV reduction is ascribed substantially to the penetration of water molecules into a specific part of the protein. Based on the thermodynamic relation, this result implies that the water penetration causes the pressure‐induced structural transition. It supports the water penetration model of pressure denaturation of proteins proposed earlier.