Auth Thorsten, Gompper Gerhard
Institut für Festkörperforschung and Institute for Advanced Simulations, Forschungszentrum Jülich, D-52425 Jülich, Germany.
Phys Rev E Stat Nonlin Soft Matter Phys. 2009 Sep;80(3 Pt 1):031901. doi: 10.1103/PhysRevE.80.031901. Epub 2009 Sep 3.
Conical inclusions in a lipid bilayer generate an overall spontaneous curvature of the membrane that depends on concentration and geometry of the inclusions. Examples are integral and attached membrane proteins, viruses, and lipid domains. We propose an analytical model to study budding and vesiculation of the lipid bilayer membrane, which is based on the membrane bending energy and the translational entropy of the inclusions. If the inclusions are placed on a membrane with similar curvature radius, their repulsive membrane-mediated interaction is screened. Therefore, for high inclusion density the inclusions aggregate, induce bud formation, and finally vesiculation. Already with the bending energy alone our model allows the prediction of bud radii. However, in case the inclusions induce a single large vesicle to split into two smaller vesicles, bending energy alone predicts that the smaller vesicles have different sizes whereas the translational entropy favors the formation of equal-sized vesicles. Our results agree well with those of recent computer simulations.
脂质双层中的锥形内含物会产生膜的整体自发曲率，该曲率取决于内含物的浓度和几何形状。例如包括整合膜蛋白和附着膜蛋白、病毒以及脂质结构域。我们提出了一个分析模型来研究脂质双层膜的出芽和囊泡化，该模型基于膜弯曲能和内含物的平移熵。如果将内含物放置在具有相似曲率半径的膜上，它们之间由膜介导的排斥相互作用会被屏蔽。因此，对于高内含物密度，内含物会聚集、诱导芽形成并最终形成囊泡。仅利用弯曲能，我们的模型就可以预测芽的半径。然而，在内含物导致单个大囊泡分裂成两个较小囊泡的情况下，仅弯曲能预测较小的囊泡大小不同，而平移熵则有利于形成大小相等的囊泡。我们的结果与最近的计算机模拟结果非常吻合。
