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The Scientific World Journal
Volume 2013 (2013), Article ID 965230, 10 pages
http://dx.doi.org/10.1155/2013/965230
Research Article

Cholesterol Induces Uneven Curvature of Asymmetric Lipid Bilayers

1Department of Physics of Biological Systems, Institute of Physics of the National Academy of Sciences of Ukraine, Prospect Nauky 46, Kiev 03680, Ukraine
2A.V. Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Leontovicha street 9, Kiev 01601, Ukraine
3Nanomedicine Laboratory, Imagery & Therapeutics, EA4662, Université de Franche-Comté, Centre Hospitalier Universitaire de Besançon, 16 Route de Gray, 25030 Besançon, France

Received 28 March 2013; Accepted 28 April 2013

Academic Editors: A. Fernandez-Barbero, D. Kopelevich, and C. Wu

Copyright © 2013 S. O. Yesylevskyy et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

A remarkable flexibility is observed in biological membranes, which allows them to form the structures of different curvatures. We addressed the question of intrinsic ability of phospholipid membranes to form highly curved structures and the role of cholesterol in this process. The distribution of cholesterol in the highly curved asymmetric DOPC/DOPS lipid bilayer was investigated by the coarse-grained molecular dynamics simulations in the membrane patches with large aspect ratio. It is shown that cholesterol induces uneven membrane curvature promoting the formation of extended flattened regions of the membrane interleaved by sharp bends. It is shown that the affinity of cholesterol to anionic DOPS or neutral DOPC lipids is curvature dependent. The cholesterol prefers DOPS to DOPC in either planar or highly curved parts of the membrane. In contrast, in the narrow interval of moderate membrane curvatures this preference is inverted. Our data suggest that there is a complex self-consistent interplay between the membrane curvature and cholesterol distribution in the asymmetric lipid bilayers. The suggested new function of cholesterol may have a biological relevance.