Role of hydrogen bonds in hydrophobicity: the free energy of cavity formation in water models with and without the hydrogen bonds

doi:10.1016/0301-4622(94)00049-2

Biophysical Chemistry

Volume 51, Issues 2–3, August 1994, Pages 279-289

https://doi.org/10.1016/0301-4622(94)00049-2 Get rights and content

Abstract

The free energies of cavity formation in water with and without hydrogen bonding potential were computed from the results of a set of Monte Carlo simulation calculations on pure liquid TIP4P water model and on the same model but with the electrostatic charges turned off (Lennard-Jones liquid). The free energies of cavity formation in the Lennard-Jones liquids are higher than or approximately equal to those in TIP4P water, depending, respectively, on whether the Lennard-Jones size parameter σ is set equal to 3.15A˚, which is the value of σ for TIP4P water, or to 2.8A˚, which is the commonly assumed value for the oxygen—oxygen distance between two hydrogen-bonded water molecules. This result indicates that changes in the hydrogen-bonded structure of water and/or in the orientational degree of freedom of water are not essential features in the production of the large free energy change upon cavity formation.

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¹: Present address: Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA 19104, USA.

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