Properties of compatible solutes in aqueous solution

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.

Highlights► Investigation of solvent structure around compatible solutes via Molecular Dynamics simulations. ► Numerical study validates strong hygroscopic effect of ectoines. ► Long range influence on water structure is indicated. ► Independent on salt concentration. ► Qualitative agreement with presented experiments.