Structural changes of interfacial water upon fluid-ripple-gel phase transitions of bilayers

All atom molecular dynamics simulations of fully hydrated dimyristoylphosphatidylcholine lipid bilayers are performed for total 9.45 μs showing a fluid to a ripple to a gel phase transition. Changes in the radial distribution functions and angular distribution functions of the interface water (IW) signify a shift from a distorted tetrahedral to a tetrahedral arrangement upon decrease in temperature at the gel phase. The potential of mean forces of the IW follow two cross-overs near both phase transitions unlike the BW. Our analyses reveal a strong correlation between bilayer phase transitions and the structural properties of the IW.