Properties of compatible solutes in aqueous solution

TL;DR

This study uses molecular dynamics simulations and experiments to analyze how compatible solutes like ectoine and hydroxyectoine interact with water, revealing their superior water retention and structuring abilities compared to urea.

Contribution

It provides new insights into the hydration properties of compatible solutes and demonstrates the importance of molecular charging and salt effects through combined simulation and experimental approaches.

Findings

Ectoine and hydroxyectoine form more ordered hydration shells than urea.

Charging of molecules is crucial for hydration sphere formation.

Salt concentration influences solute-water interactions.

Abstract

We have performed Molecular Dynamics simulations of ectoine, hydroxyectoine and urea in explicit solvent. Special attention has been spent on the local surrounding structure of water molecules. Our results indicate that ectoine and hydroxyectoine are able to accumulate more water molecules than urea by a pronounced ordering due to hydrogen bonds. We have validated that the charging of the molecules is of main importance resulting in a well defined hydration sphere. The influence of a varying salt concentration is also investigated. Finally we present experimental results of a DPPC monolayer phase transition that validate our numerical findings.