Benchmarking the thermodynamic analysis of water molecules around a model beta sheet.

TitleBenchmarking the thermodynamic analysis of water molecules around a model beta sheet.
Publication TypeJournal Article
Year of Publication2012
AuthorsHuggins DJ
JournalJ Comput Chem
Volume33
Issue15
Pagination1383-92
Date Published2012 Jun 05
ISSN1096-987X
KeywordsBenchmarking, Models, Molecular, Protein Structure, Secondary, Proteins, Thermodynamics, Water
Abstract

Water molecules play a vital role in biological and engineered systems by controlling intermolecular interactions in the aqueous phase. Inhomogeneous fluid solvation theory provides a method to quantify solvent thermodynamics from molecular dynamics or Monte Carlo simulations and provides an insight into intermolecular interactions. In this study, simulations of TIP4P-2005 and TIP5P-Ewald water molecules around a model beta sheet are used to investigate the orientational correlations and predicted thermodynamic properties of water molecules at a protein surface. This allows the method to be benchmarked and provides information about the effect of a protein on the thermodynamics of nearby water molecules. The results show that the enthalpy converges with relatively little sampling, but the entropy and thus the free energy require considerably more sampling to converge. The two water models yield a very similar pattern of hydration sites, and these hydration sites have very similar thermodynamic properties, despite notable differences in their orientational preferences. The results also predict that a protein surface affects the free energy of water molecules to a distance of approximately 4.0 Å, which is in line with previous work. In addition, all hydration sites have a favorable free energy with respect to bulk water, but only when the water-water entropy term is included. A new technique for calculating this term is presented and its use is expected to be very important in accurately calculating solvent thermodynamics for quantitative application.

DOI10.1002/jcc.22971
Alternate JournalJ Comput Chem
PubMed ID22457119
PubMed Central IDPMC4768347
Grant List091058 / / Wellcome Trust / United Kingdom
G0700651 / / Medical Research Council / United Kingdom
G1001522 / / Medical Research Council / United Kingdom