Open AccessEnthalpic and Entropic Contributions to Hydrophobicity
Author(s) -
Michael Schauperl,
Maren Podewitz,
Birgit J. Waldner,
Klaus R. Liedl
Publication year - 2016
Publication title -
journal of chemical theory and computation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.001
H-Index - 185
eISSN - 1549-9626
pISSN - 1549-9618
DOI - 10.1021/acs.jctc.6b00422
Subject(s) - solvation , entropic force , enthalpy , molecule , hydrophobic effect , chemistry , thermodynamic integration , chemical physics , thermodynamics , molecular dynamics , folding (dsp implementation) , statistical physics , computational chemistry , physics , organic chemistry , engineering , electrical engineering
Hydrophobic hydration plays a key role in a vast variety of biological processes, ranging from the formation of cells to protein folding and ligand binding. Hydrophobicity scales simplify the complex process of hydration by assigning a value describing the averaged hydrophobic character to each amino acid. Previously published scales were not able to calculate the enthalpic and entropic contributions to the hydrophobicity directly. We present a new method, based on Molecular Dynamics simulations and Grid Inhomogeneous Solvation Theory, that calculates hydrophobicity from enthalpic and entropic contributions. Instead of deriving these quantities from the temperature dependence of the free energy of hydration or as residual of the free energy and the enthalpy, we directly obtain these values from the phase space occupied by water molecules. Additionally, our method is able to identify regions with specific enthalpic and entropic properties, allowing to identify so-called "unhappy water" molecules, which are characterized by weak enthalpic interactions and unfavorable entropic constraints.