Inhomogeneity of polylysine adsorption layers on lipid membranes revealed by theoretical analysis of electrokinetic data and molecular dynamics simulationsстатья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 3 ноября 2021 г.
Аннотация:The adsorption of large polycations on a charged lipid membrane is qualitatively different from the smallinorganic cations, which almost uniformly populate the membrane surface. We assume that the polycationicadsorption layer might be laterally inhomogeneous starting from a certain polymer length, and thiseffect can be more visible for membranes with low anionic lipid content. To study systems with inhomogeneousadsorption layers, we carried out electrokinetic measurements of mobility of liposomes containinganionic and neutral phospholipids in the presence of polylysine molecules. Some of these systemswere simulated by all-atom molecular dynamics. Here we proposed a theoretical approach accountingfor the formation of separated regions at the membrane surface, which differ in charge density and surfacepotential. Our model allowed us to determine the adsorption layer’s geometric parameters such assurface coverage and surface-bound monomer fraction of polymer, which correlate with the moleculardynamics (MD) simulations. We demonstrated that the configuration polylysine adopts on the membranesurface (tall or planar) depends on the polymer/membrane charge ratio. Both theory and MD indicatea decrease in the anionic lipid content, alongside with a decrease in the bound monomer fraction andcorresponding increase in the extension length of the adsorbed polymers.