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Application of reference‐modified density functional theory: Temperature and pressure dependences of solvation free energy
Author(s) -
Sumi Tomonari,
Maruyama Yutaka,
Mitsutake Ayori,
Mochizuki Kenji,
Koga Kenichiro
Publication year - 2018
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.25101
Subject(s) - solvation , thermodynamics , chemistry , molecule , density functional theory , implicit solvation , ideal gas , computational chemistry , physics , organic chemistry
Recently, we proposed a reference‐modified density functional theory (RMDFT) to calculate solvation free energy (SFE), in which a hard‐sphere fluid was introduced as the reference system instead of an ideal molecular gas. Through the RMDFT, using an optimal diameter for the hard‐sphere reference system, the values of the SFE calculated at room temperature and normal pressure were in good agreement with those for more than 500 small organic molecules in water as determined by experiments. In this study, we present an application of the RMDFT for calculating the temperature and pressure dependences of the SFE for solute molecules in water. We demonstrate that the RMDFT has high predictive ability for the temperature and pressure dependences of the SFE for small solute molecules in water when the optimal reference hard‐sphere diameter determined for each thermodynamic condition is used. We also apply the RMDFT to investigate the temperature and pressure dependences of the thermodynamic stability of an artificial small protein, chignolin, and discuss the mechanism of high‐temperature and high‐pressure unfolding of the protein. © 2017 Wiley Periodicals, Inc.