Murtola Teemu, Falck Emma, Patra Michael, Karttunen Mikko, Vattulainen Ilpo
Laboratory of Physics and Helsinki Institute of Physics, Helsinki University of Technology, P.O. Box 1100, FIN-02015 HUT, Finland.
J Chem Phys. 2004 Nov 8;121(18):9156-65. doi: 10.1063/1.1803537.
We construct a coarse-grained (CG) model for dipalmitoylphosphatidylcholine (DPPC)/cholesterol bilayers and apply it to large-scale simulation studies of lipid membranes. Our CG model is a two-dimensional representation of the membrane, where the individual lipid and sterol molecules are described by pointlike particles. The effective intermolecular interactions used in the model are systematically derived from detailed atomic-scale molecular dynamics simulations using the Inverse Monte Carlo technique, which guarantees that the radial distribution properties of the CG model are consistent with those given by the corresponding atomistic system. We find that the coarse-grained model for the DPPC/cholesterol bilayer is substantially more efficient than atomistic models, providing a speedup of approximately eight orders of magnitude. The results are in favor of formation of cholesterol-rich and cholesterol-poor domains at intermediate cholesterol concentrations, in agreement with the experimental phase diagram of the system. We also explore the limits of the coarse-grained model, and discuss the general validity and applicability of the present approach.
我们构建了一个用于二棕榈酰磷脂酰胆碱（DPPC）/胆固醇双层膜的粗粒化（CG）模型，并将其应用于脂质膜的大规模模拟研究。我们的CG模型是膜的二维表示，其中单个脂质和甾醇分子由点状粒子描述。模型中使用的有效分子间相互作用是通过逆蒙特卡罗技术从详细的原子尺度分子动力学模拟中系统推导出来的，这保证了CG模型的径向分布特性与相应原子系统给出的特性一致。我们发现，DPPC/胆固醇双层膜的粗粒化模型比原子模型效率高得多，速度提升了约八个数量级。结果支持在中等胆固醇浓度下形成富含胆固醇和贫胆固醇区域，这与该系统的实验相图一致。我们还探索了粗粒化模型的局限性，并讨论了本方法的一般有效性和适用性。
