Numerical study of water clusters at protein interfaces

Abstract

We simulate by Monte Carlo method how the protein interface in aqueous solution affects the formation of clusters whose connectivity length is related to the thermodynamic correlation length of water, following the definition of the "correlated percolation". We consider a model for a protein in a water monolayer that has been shown to reproduce the anomalies of water, including the occurrence of two specific heat maxima at low temperature and pressure in a region that approaches a liquid-liquid critical point. We show that the maxima can be characterized in terms of percolation quantities at any temperature and pressure. Furthermore, we find that the protein interface promotes the formation of water clusters, a result that might be relevant for the biological functions of the proteins