Abstract
Trehalose acts as a good protectant against various water stresses such as desiccation and freezing. The water replacement hypothesis has been proposed as a possible mechanism by which trehalose protects biological components such as membrane and proteins in low water activity. Here, to investigate this hypothesis at atomic resolution, molecular dynamics simulations were carried out for trehalose/phospholpid bilayer systems, where the bilayer was constructed from 1-palmitoyl 2-oleoyl phosphatidylcholine (POPC). Trehalose molecules were dissolved in the interbilayer medium at a concentration of 0.133 mol/kg or 1.220 mol/kg. After a 10 ns simulation for each system, we analyzed the hydrogen bond network formed among trehalose, water and the head group of POPC. In consequence, it was found that a part of the trehalose molecules directly hydrogen bond to the head group of POPC without being interrupted by any water molecules and that the stability of the lipid bilayer increases with an increase in trehalose concentration. These results support the validity of the water replacement hypothesis.
