Comparison of mesoscopic phospholipid–water models

Abstract

In this study we show how a coarse-grained model of a phospholipid can be developed and we study the parameter sets applied to the formation of a coarse-grained dimyristoyl phosphatidyl choline (DMPC) bilayer. We create a model comprising a head group of three hydrophilic beads, to which two hydrophobic tails are connected. From results obtained with molecular dynamics simulations on a single lipid in water, a bond-bending potential between three subsequent beads was added. Using a bead volume of 90 ų, we reproduce the experimental values of the area per lipid and the hydrophobic thickness. There is no linear relation between the repulsion parameter a_ij and the level of coarse graining. The key factor in the formation of a lipid bilayer is the difference between the water–water and the water–hydrophobic tail repulsion parameters.