Cruzeiro-Hansson L, Ipsen J H, Mouritsen O G
Laboratory of Applied Mathematical Physics, Technical University of Denmark, Lyngby.
Biochim Biophys Acta. 1989 Feb 27;979(2):166-76. doi: 10.1016/0005-2736(89)90432-x.
A theoretical analysis of the effects of intrinsic molecules on the lateral density fluctuations in lipid bilayer membranes is carried out by means of computer simulations on a microscopic interaction model of the gel-to-fluid chain-melting phase transition. The inhomogeneous equilibrium structures of gel and fluid domains, which in previous work (Cruzeiro-Hansson, L. and Mouritsen, O.G. (1988) Biochim. Biophys. Acta 944, 63-72) were shown to characterize the transition region of pure lipid membranes, are here shown to be enhanced by intrinsic molecules such as cholesterol. Cholesterol is found to increase the interfacial area and to accumulate in the interfaces. The interfacial area, the average cluster size, the lateral compressibility, and the membrane area are calculated as functions of temperature and cholesterol concentration. It is shown that the enhancement by cholesterol of the lateral density fluctuations and the lipid-domain interfacial area is most pronounced away from the transition temperature. The implications of the results are discussed in relation to passive ion permeability and function of interfacially active enzymes such as phospholipase.
通过对凝胶 - 流体链熔化相变的微观相互作用模型进行计算机模拟，对内在分子对脂质双分子层膜横向密度涨落的影响进行了理论分析。在之前的工作中（Cruzeiro - Hansson, L.和Mouritsen, O.G.（1988年），《生物化学与生物物理学报》944卷，63 - 72页）表明，凝胶域和流体域的非均匀平衡结构表征了纯脂质膜的转变区域，此处表明这些结构会因胆固醇等内在分子而增强。发现胆固醇会增加界面面积并在界面处积累。计算了界面面积、平均簇尺寸、横向压缩性和膜面积作为温度和胆固醇浓度的函数。结果表明，胆固醇对横向密度涨落和脂质域界面面积的增强作用在远离转变温度时最为明显。结合被动离子渗透性和磷脂酶等界面活性酶的功能讨论了这些结果的意义。
