Center for Relativistic Laser Science

2019 123rd KCS 

Lipid bilayer is an excellent model system for investigating membrane structures and its hydration water. These membrane and hydration water have been studied by various experiments and computational studies. To observe detailed interactions between lipid head groups and their hydration water, we performed molecular dynamics (MD) simulation for the lipid multi-bilayer. From hydrogen bond number analysis, radial distribution, and orientational distribution of hydration water, we checked a strong interaction between phosphate group and water molecule, even to the second hydration shell. In contrast, a choline-associated water shows weak interaction with choline group. And, results from orientational relaxation and FT-IR spectroscopy for the hydration water revealed slow water dynamics and red-shifted absorption spectrum induced by the phosphate group, indicating the strong interaction between the phosphate group and its hydration water consistently. In this study, our results are in good agreement with experimental results and give insight into the interfacial water research at the lipid membrane surfaces.