The structural order of protein hydration water

TL;DR

This study uses molecular dynamics simulations and a new structural descriptor to show that proteins promote local structural order in hydration water without significantly affecting hydrogen-bond strength, enhancing understanding of biomolecular hydration.

Contribution

The paper introduces a novel structural descriptor for analyzing hydrogen-bond networks at the protein-water interface and demonstrates that proteins promote local order in hydration water.

Findings

Proteins promote local structural ordering of hydration water.

Protein has negligible effect on hydrogen-bond strength.

Findings provide new insights into protein hydration mechanisms.

Abstract

The ability of water to dissolve biomolecules is crucial for our life. It has been shown that protein has a profound effect on the behavior of water in its hydration shell, which in turn affects the structure and function of the protein. However, there is still no consensus on whether protein promotes or destroys the structural order of water in its hydration shell until today, because of the lack of proper structural descriptor incorporating hydrogen-bond (H-bond) information for water at the protein/water interface. Here we performed all-atom molecular dynamics simulations of lysozyme protein in water and analyzed the H-bond structure of protein hydration water by using a newly developed structural descriptor. We find that the protein promotes local structural ordering of the hydration water while has a negligible effect on the strength of individual H-bond. These findings are fundamental to the structure and function of biomolecules and provide new insights into the hydration of protein in water.