Water at interface with proteins

TL;DR

This paper reviews experimental and theoretical studies on the properties of water at protein interfaces, focusing on how water dynamics influence protein stability and activity, especially at low temperatures.

Contribution

It synthesizes recent experimental data and theoretical models to better understand water's role in protein behavior and stability at interfaces and low temperatures.

Findings

Water exhibits a crossover in dynamics at low temperatures near proteins.

Interfacial water properties are linked to protein cold denaturation.

Simulations suggest hydrogen bond strengthening affects protein stability.

Abstract

Water is essential for the activity of proteins. However, the effect of the properties of water on the behavior of proteins is only partially understood. Recently, several experiments have investigated the relation between the dynamics of the hydration water and the dynamics of protein. These works have generated a large amount of data whose interpretation is debated. New experiments measure the dynamics of water at low temperature on the surface of proteins, finding a qualitative change (crossover) that might be related to the slowing down and stop of the protein's activity (protein glass transition), possibly relevant for the safe preservation of organic material at low temperature. To better understand the experimental data several scenarios have been discussed. Here, we review these experiments and discuss their interpretations in relation with the anomalous properties of water. We summarize the results for the thermodynamics and dynamics of supercooled water at an interface. We consider also the effect of water on protein stability, making a step in the direction of understanding, by means of Monte Carlo simulations and theoretical calculations, how the interplay of water cooperativity and hydrogen bonds interfacial strengthening affects the protein cold denaturation.