纳米尺度理论与计算-生物膜（lipid bilayer）与细胞内化（endocytosis）模拟.pdfVIP

纳米尺度理论与计算 生物膜（lipid bilayer ）与细胞 内化（endocytosis ）模拟 生物膜是组成细胞的重要成分 1. The outmost barrier of the cell 2. Control transport into/from the cell 3. 30% of eukaryotic proteins are associated with membranes (membrane proteins, receptors) 4. 50% of current drugs target membrane proteins 5. Without membranes you die (van der Spoel, 2007) 2 细胞膜的几个功能 Fluid mosaic model Describes the organization of cell membranes Phospholipids drift and move like a fluid The bilayer is a mosaic mixture of phospholipids, steroids, proteins, and other molecules What is a lipid bilayer ? DPPC-Dipalmitoylphosphatidylcholine DOPG-Dioleoylphosphatidylglycerol POPE-Palmitoyloleoylphosphatidyletanolamine DPC –Dodecylphosphocholine Cholesterol 胆固醇 磷脂酰胆碱（卵磷脂） 磷脂酰乙醇胺（脑磷脂） 磷脂酰甘油 磷脂酰丝氨酸 磷脂酰肌醇 Membrane composition within cells J Cell Science, 124, 5 (2011) Mammals in dark blue and yeast in light blue Nature Rev: Mol Cel Bio 9, 112 (2008) Lipid conformations •Large headgroups, single chain: Lipids form micelles •Higher concentration: hexagonal phases •There are also inverted micelles and hexagonal phases •Similar size headgroup/chains: bilayers or vesicles Key physical properties of lipid bilayers • Thickness. •increases with the length of the hydrocarbon chains •decreases with the number of unsaturated bond in chains •decreases with temperature • Area per molecule •increases with the length of the hydrocarbon chains •increases with the number of unsaturated bond in chains •increases with temperature •also depends on the properties of polar region Key physical properties of lipid bilayer