On the dynamics of molecular self-assembly and the structural analysis of bilayer membranes using coarse-grained molecular dynamics simulations.

Abstract We present a molecular dynamics simulation study of the self-assembly of coarse-grained lipid molecules from unbiased random initial configurations. Our lipid model is based on a well-tried CG polymer model with an additional potential that mimics the hydrophobic properties of lipid tails. We find that several stages of self-organization of lipid clusters are involved in the dynamics of bilayer formation and that the resulting equilibrium structures sensitively depend on the strength of hydrophobic interactions h c of the lipid tails and on temperature T . The obtained stable lipid membranes are quantitatively analyzed with respect to their local structure and their degree of order. At equilibrium, we obtain self-stabilizing bilayer membrane structures that exhibit a bending stiffness κ B and compression modulus K C comparable to experimental measurements under physiological conditions. We present a phase diagram of our lipid model which covers a sol–gel transition, a liquid (or gel-like) phase including stable bilayer structures and vesicle formation, as well as a quasi–crystalline phase. We also determine the exact conditions for temperature T and degree of hydrophobicity h c for stable bilayer formation including closed vesicles.