Ferroelectric hydration shells around proteins: Electrostatics of the protein/water interface

TL;DR

This paper reveals that protein hydration shells form ferroelectric clusters that significantly influence electrostatic fluctuations, challenging traditional linear-response models and highlighting a slow, non-Gaussian electrostatic dynamics linked to protein transitions.

Contribution

It uncovers ferroelectric hydration shells around proteins and demonstrates their impact on electrostatic fluctuation behavior, introducing a new mesophase in protein-water interfaces.

Findings

Hydration shells exhibit ferroelectric polarization.

Electrostatic fluctuations deviate from linear response predictions.

A slow (~1 ns) electrostatic component correlates with protein dynamical transition.

Abstract

Numerical simulations of hydrated proteins show that protein hydration shells are polarized into a ferroelectric cluster with a large magnitude of its average dipole moment. The emergence of this new mesophase dramatically alters the statistics of electrostatic fluctuations at the protein/water interface. The linear-response relation between the average electrostatic potential and its variance breaks down, with the breadth of the electrostatic noise far exceeding the expectations of the linear response theories. The dynamics of these non-Gaussian electrostatic fluctuations are dominated by a slow (~ 1 ns) component which freezes in at the temperature of dynamical transition of proteins.