CHARACTERIZATION OF MEMBRANE LIPID DOMAINS

在模型膜和生物膜中，脂质都有能力 存在于不同于其他横向域的横向域中 作文中的分组。然而，这一安排 生物膜内的磷脂分子物种不是 很好理解。在拟议的工作中，化学成分 合成脂质混合物中的脂相和脂结构域， 分离的大肠杆菌脂类和完整的细胞质 将对大肠杆菌的细胞膜进行研究。荧光 将使用对位芳酰基磷脂的极化来评估 脂肪相存在，而最近的化学交联 邻近的脂质将被用来确定脂质的排列 膜液相脂。磷脂酰乙醇胺 物种将通过胺特定的试剂进行交联， 二甲基硫酰亚胺及其高压分析产物 液体和气-液色谱。脂类物种，映射到一个 完整膜中的相和结构域，将定位于 使用非特异性脂质转移的内或外单分子层 牛肝中的蛋白质及其化学标记 三硝基苯磺酸。这些研究将考察 脂肪酸代谢发生突变的大肠杆菌的细胞膜。 在各种脂肪酸补充剂的作用下生长， 这些细胞由于它们的脂类而产生功能缺陷。 作文。这里描述的化学和物理研究 将集成到一个更清晰定义的膜模型中 结构，从长远来看，这将提供一个联系的基础 膜脂拓扑结构对膜功能的影响。

In both model and biological membranes, lipids have the capability of existing in lateral domains which differ from other lateral groupings in composition. However, the arrangement of phospholipid molecular species within biological membranes is not well understood. In the proposed work, the chemical composition of lipid phases and lipid domains in synthetic lipid mixtures, isolated Escherichia coli lipids, and the intact cytoplasmic membrane of E. coli will be investigated. Fluorescence polarization of parinaroyl phospholipids will be used to assess the lipid phases present, while chemical crosslinking of nearest neighbor lipids will be used to determine the lipid arrangement of the membrane fluid phase lipids. Phosphatidylethanolamine species will be crosslinked by the amine-specific reagent, dimethylsuberimidate, and the products analyzed by high pressure liquid and gas-liquid chromatography. Lipid species, mapped to a phase and domain in intact membranes, will be localized to the inner or outer monolayer using the nonspecific lipid transfer protein from bovine liver and by chemical labelling with trinitrobenzenesulfonic acid. These studies will examine the membranes of E. coli with mutations in fatty acid metabolism. Grown with various fatty acid supplements, the membranes of these cells develop functional defects due to their lipid compositions. The chemical and physical studies described here will be integrated into a more clearly defined model of membrane structure, which, in the long term, will provide a basis to relate membrane lipid topology to membrane function.