Structural Requirements for Protein Membrane Assembly

这个项目解决的问题是， 包含在分泌的或膜的氨基酸序列中 蛋白质决定了插入或 通过膜。 这是细胞中的一个基本问题 生物学 带正电荷的残基，通常位于 蛋白质跨膜片段的边界，似乎 参与指定膜蛋白的方向。 这项建议详细审查了在何种程度上积极 带电残基在这一过程中发挥作用， 哪种蛋白质获得了它们独特的膜拓扑结构， 土工坐骨结肠。 该提案的目的是：1、确定 是否内膜蛋白，像其他输出蛋白一样， E.大肠杆菌的细胞膜需要分子伴侣 组装; 2，从基因上定义蛋白质的部分， 参与其膜组件; 3，评估 简单膜和复杂膜的膜插入机制 蛋白质; 4、建立一般的正电荷作用 结构域的蛋白质方向;和5，以确定如何 带正电荷的残基对拓扑结构产生影响。 这 工作将与E。大肠杆菌前导肽酶， 光合反应中心、前衣、乳糖通透酶和 外膜蛋白A将使用各种方法， 包括体内和体外技术。 蛋白酶图谱和 生物化学方法将决定正电荷如何 对蛋白质拓扑结构的影响 这些对蛋白质膜组装的研究最终将有助于 回答了细胞生物学中的一些基本问题 关于蛋白质区室化。

This project addresses the problem of how the information contained in the amino acid sequence of a secreted or a membrane protein determines the precise topology of insertion into or through the membrane. This is a fundamental problem in cell biology. Positively charged residues, often found located near the boundaries of transmembrane segments of proteins, appear to be involved in specifying the orientation of membrane proteins. This proposal examines in detail to what extent positively charged residues play a part in this process and the mechanism by which proteins obtain their unique membrane topology in Escherischia coli. The aims of the proposal are: 1, to determine whether inner membrane proteins, like other exported proteins in E. coli, require molecular chaperones for their membrane assembly; 2, to define genetically the parts of the proteins that participate in their membrane assembly; 3, to evaluate the mechanisms of membrane insertion for simple and complex membrane proteins; 4, to establish the general role of positively charged domains in protein orientation; and 5, to determine how positively charged residues exert their effect on topology. This work will be done with the E. coli leader peptidase, subunit H of the photosynthetic reaction center, procoat, lac permease, and outer membrane protein A. A variety of approaches will be used, including in vivo and in vitro techniques. Protease mapping and biochemical methods will determine how positive charges exert their effect on protein topology. These studies in protein membrane assembly will eventually help answer some of the fundamental questions in cellular biology concerning protein compartmentalization.