HEAD GROUP WATER INTERACTIONS IN LIPID BILAYERS - A COMPARISON BETWEEN DMPC-BASED AND DLPE-BASED LIPID BILAYERS

Molecular dynamics simulations on dimyristoylphosphatidylcholine (DMPC)-based lipid bilayers are reported. The resulting trajectory is compared to a previous one for dilauroylphosphatidylethanolamine (DLPE)-based lipid bilayers. The major difference between these two systems appears to be the formation of a clathrate shell at the surface of the DMPC-based lipid bilayer. This arises due to the presence of the hydrophobic -N(CH3)3+ group in DMPC which is replaced by the hydrophilic -NH3+ group in DLPE. Implications of this observation on the hydration force problem are discussed.