Osmolytes are small soluble molecules that influence osmotic pressure and help maintain cell structure. Trimethylamine N-oxide (TMAO) is a soluble small molecule found in many deep-sea animals at high concentrations (up to 386 mmol/kg) and is believed to be a key aspect of pressure adaptation in these organisms, but the mechanism is a matter of discussion and debate. In order to assess the pressure dependent properties of osmolytes in molecular dynamics simulations, we performed a series of molecular dynamics simulations of osmolytes as a function of pressure. We implemented a method to determine the osmotic coefficients of NaCl and TMAO in the CHARMM forcefield. We have also performed simulations of simple membranes solvated by TMAO and water mixtures in order to assess pressure dependent effects of osmolytes on membranes.
Beris et al. (Sun,) studied this question.