Yesylevskyy S O, Demchenko A P, Kraszewski S, Ramseyer C
Department of Physics of Biological Systems, Institute of Physics of the National Academy of Sciences of Ukraine, Prospect Nauky 46, Kiev 03680, Ukraine.
ScientificWorldJournal. 2013 May 16;2013:965230. doi: 10.1155/2013/965230. Print 2013.
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.
在生物膜中观察到显著的灵活性，这使其能够形成不同曲率的结构。我们研究了磷脂膜形成高度弯曲结构的内在能力问题以及胆固醇在此过程中的作用。通过在具有大纵横比的膜片中进行粗粒度分子动力学模拟，研究了胆固醇在高度弯曲的不对称DOPC/DOPS脂质双层中的分布。结果表明，胆固醇会诱导不均匀的膜曲率，促进膜形成由急剧弯曲交错的延伸扁平区域。结果表明，胆固醇对阴离子型DOPS或中性DOPC脂质的亲和力取决于曲率。在膜的平面或高度弯曲部分，胆固醇更倾向于DOPS而非DOPC。相反，在中等膜曲率的狭窄区间内，这种偏好则相反。我们的数据表明，在不对称脂质双层中，膜曲率与胆固醇分布之间存在复杂的自洽相互作用。所提出的胆固醇的新功能可能具有生物学相关性。
