(671d) A Computational Study of the Molecular Structure and Permeability of Multi-Component Lipid Membranes in the Gel Phase

Biological membranes typically consist of several lipid components, including phospholipids, fats, sterols, and alcohols. Although the structure and permeability of the bilayers is known to be dependent on factors such as the type of lipid head group, chain length, and chain packing, the details of these dependencies are not fully understood.  A better understanding of the relationship between composition, structure, and permeability is, however, needed to improve, replicate, or reduce, as applicable, the barrier function of biological membranes. Molecular dynamics simulation has been widely used to study lipid bilayers as they provide access to molecular level information that is hard to determine experimentally. Thus far, the effect of sterols (cholesterol in particular) on the structure (e.g., the area-per-lipid, repeat distance, tilt angle, etc.), water diffusion, and phase behavior of phospholipid bilayers has received considerable attention [1,2], however, the effects of other molecules has been largely overlooked. Here, we investigate the effect of various alcohols, acids and esters on the structure and permeability of phospholipid bilayers in the gel phase. Comparisons of simulations for different lipid bilayer compositions provide insight into the influence of head group interaction, tail length and tail asymmetry, and how these properties can be leveraged to tune the permeability behavior of the systems to better replicate biologically relevant membranes.

References:

[1] F. de Meyer and B. Smit, Proc. Nat. Ac. Sci., 106, 3654 (2009).

[2] C.-Y. Cheng, L. L. C. Olijve, R. Kausik, and S. Han, J. Chem. Phys., 141, 22D513 (2014).