MOLECULAR-DYNAMICS SIMULATION OF UNSATURATED LIPID BILAYERS AT LOW HYDRATION - PARAMETERIZATION AND COMPARISON WITH DIFFRACTION STUDIES

A potential energy function for unsaturated hydrocarbons is proposed a nd is shown to agree well with experiment, using molecular dynamics si mulations of a water/octene interface and a dioleoyl phosphatidylcholi ne (DOPC) bilayer. The simulation results verify most of the assumptio ns used in interpreting the DOPC experiments, but suggest a few that s hould be reconsidered, Comparisons with recent results of a simulation of a dipalmitoyl phosphatidylcholine (DPPC) lipid bilayer show that d isorder is comparable, even though the temperature, hydration level, a nd surface area/lipid for DOPC are lower. These observations highlight the dramatic effects of unsaturation on bilayer structure.