Quasi-Atomistic Approach to Modeling of Liposomes

Small-angle X-ray scattering is an important structural tool for studying biological membranes; however, interpretation of scattering data remains a challenging problem. In most cases, analysis makes it possible to determine some structural parameters and the electron density profile of lipid bilayers, but no methods providing more detailed information (e.g., about the structural organization of vesicles) have been proposed yet. An approach making it possible to determine the main integral characteristics of liposomes using small-angle scattering is presented in this study. Within this approach a quasi-atomic model of liposome is built from individual lipid molecules, which form a sphere or a hollow ellipsoid. The method has been implemented in a computer program, verified on experimental small-angle X-ray scattering data, and proposed to analyze the structure of lipid vesicles and their interactions with proteins.