Molecular dynamics study of the lipid bilayers: Effects of the chain branching on the structure and dynamics

Wataru Shinoda, Masuhiro Mikami, Teruhiko Baba, and Masakatsu Hato

AIP Conference series, 708, 352-353 (2004).

We investigated effects of lipid chain branching on structural and dynamical properties of the lipid bilayers by a comparative molecular dynamics simulation of dipalmitoyl phosphatidylcholine (DPPC) and diphytanoyl phosphatidylcholine (DPhPC) bilayers. Gauche-trans isomerization rate at the dihedrals along the hydrophobic main chains was significantly reduced by chain branching. The slower conformational motion of branched chains lead to slower wobbling of the chain and slower rotational and translational motions of the lipid molecules, compared with straight-chained counterpart. In contrast, head group motion was slightly enhanced by the chain branching. The slower dynamics of the branched hydrophobic chains account for the high structural bilayer stability and low solute permeability of the branched DPhPC bilayer.