Effects of lipid packing on polymorphic phase behavior and membrane properties.
Effects of lipid packing on polymorphic phase behavior and membrane properties.
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DOI：
10.1073/pnas.86.15.5825
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发表时间：
1989-08
影响因子：
11.1
通讯作者：
S. Hui;Arindam Sen
中科院分区：
文献类型：
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作者：
S. Hui;Arindam Sen
双层形式的磷脂分子的自组装根据代表分子间力的等效分子形状来考虑。每个磷脂头基的等效尺寸通过净原子体积加上相关水分子的体积来近似，该水分子源自水/烃分配实验。不饱和酰基链的当量长度源自色谱测量的保留时间数据。各种磷脂单层的自发曲率是根据其等效分子形状计算的，并使用已知的弯曲模量计算将它们压平至双层平面所需的能量。随着弯曲能量的增加，混合物对磷脂酶 A2 的敏感性增加，通过磷脂交换蛋白促进脂质转移速率、对羧基荧光素的渗透性、人红细胞蛋白的掺入以及通过 Ca-ATP 酶从重构囊泡中的肌浆网进行钙转运。当计算应用于九种细胞膜的已知脂质成分时，发现蛋白质/脂质比率和磷脂/胆固醇比率分别与磷脂的潜在弯曲能呈正相关和负相关。符合双层相的能量消耗可能是关于膜的活性和生物发生的重要物理参数。
The self assembly of phospholipid molecules in the bilayer form was considered in terms of equivalent molecular shapes representing intermolecular forces. The equivalent size of each phospholipid headgroup was approximated by the net atomic volume plus the volume of the associated water molecules, which was derived from water/hydrocarbon partitioning experiments. The equivalent lengths of unsaturated acyl chains were derived from the retention time data from chromatographic measurements. The spontaneous curvature of various phospholipid monolayers was calculated from their equivalent molecular shapes, and the energy required to flatten them to the bilayer plane was calculated, using the known bending modulus. With increasing bending energy, the mixtures showed increasing susceptibility to phospholipase A2, facilitated lipid transfer rate by phospholipid exchange proteins, permeability to carboxyfluorescein, incorporation of human erythrocyte proteins, and calcium transport by Ca-ATPase from sarcoplasmic reticulum in reconstituted vesicles. When the calculation was applied to known lipid compositions of nine cellular membranes, the protein/lipid ratio and phospholipid/cholesterol ratio were found to have a positive and a negative correlation, respectively, with the latent bending energy of the phospholipids. The energy expense in conforming to a bilayer phase may be an important physical parameter regarding the activity and the biogenesis of membranes.