Modelling and molecular dynamics simulation studies on a hexagonal glycolipid assembly

The hexagonal columnar phase (HI) of an aqueous formulation of octyl β-glucoside with 67 % lipid content was modelled and 15-ns molecular dynamics simulation was performed. Initial investigations on the aggregation size led to good correlation of simulation and experimental d-spacing for a 12 molecule cylinder core. The corresponding hexagonal phase was stable over the entire simulation time and provided conclusive local density profiles. Hydrogen bonding analyses showed only minor differences in the bonding profile between the hexagonal and a previously reported micellar phase. However, the glycoside interaction decreases with increasing curvature, i.e. from a lamellar assembly over the hexagonal phase to the micelle, while the opposite behaviour applies for interactions with water. A view into the water dynamics revealed an anisotropic-correlated diffusion process with higher mobility along the cylinder axes than perpendicular to them.