Decomposition of Friction Coefficients to Analyze Hydration Effects on a C$_{60}$(OH)$_{\rm n}$

TL;DR

This study introduces a method to decompose molecular friction coefficients to better understand hydration effects on macromolecular diffusion, revealing that surface properties influence hydration and diffusion.

Contribution

A novel decomposition method for molecular friction coefficients was developed and applied to fullerenols, elucidating hydration effects on diffusion behavior.

Findings

Hydrophilic groups exhibit larger friction coefficients than hydrophobic groups.

Hydration effects depend on both functional groups and surface roughness.

The approach helps explain changes in protein diffusion with conformational changes.

Abstract

To analyze hydration effects on macromolecular diffusion, the friction coefficients of macromolecules were examined using molecular dynamics simulations with an all-atom model. In the present study, a method was introduced to decompose the molecular friction coefficient into the contributions for each site on the macromolecule. The method was applied to several fullerenols in ambient water. The friction coefficients for the hydrophilic part, such as the OH group, were larger than those for the hydrophobic part, such as the C. The hydration effect did not depend only on the kind of functional group but also on surface roughness. This approach would be useful in explaining the experimentally observed large changes in diffusion coefficients of proteins that were accompanied by conformation changes.