Analysis of local dynamic heterogeneities and hydrophobic surface properties of lipid bilayers is an important step toward understanding of the physical processes underlying formation of lipid domains and molecular mechanisms of the so-called “membrane response” observed upon binding of external molecules to cell membranes. Here, we used atomistic molecular dynamics simulations to address these problems and study structural/amphiphilic “portrait” of a large series of model bilayer membranes (1,2). Rearrangements of membranes upon binding of antimicrobial peptides and association of transmembrane helices were investigated as well (3,4).It was shown that the water-lipid interface of biomembranes represents a highly dynamic and “mosaic” picture, whose parameters depend on the bilayer composition. Formation of such heterogeneities is caused by various intermolecular interactions between lipids, water and ions. Because clustering of the components is determined by a thin balance of differently directed factors, even their minor changes can induce serious rearrangements on the membrane surface. These issues still resist easy experimental characterization.Probably, these phenomena are indispensable for fast mass/energy transfer near the water/membrane boundary, thus regulating diffusion of molecules in this functionally important area: e.g., approaching of ligands to membrane receptors, delivery of proteins to their sites of insertion into membrane, and so on. Putative role of local heterogeneities and collective phenomena in lipid/water systems is discussed.References[1] D.V. Pyrkova et al., Soft Matter 7 (2011) 2569.[2] D.V. Pyrkova et al., J. Biomol. Struct. Dyn. 31 (2013) 87.[3] A.A. Polyansky et al., J. Amer. Chem. Soc. 134 (2012) 14390.[4] A.A. Polyansky et al., J. Amer. Chem. Soc. 135 (2013) 8105.