Genetic Analysis of Complex Membrane Protein Insertion

这项研究的目的是更好地了解膜蛋白是如何获得其最终结构的。实验分析了具有简单和复杂拓扑结构的两种细胞膜蛋白--丝氨酸化学受体和&gt；lac&gt；通透酶。这项研究旨在帮助阐明这些蛋白质的跨膜拓扑结构是如何产生的，以及这些拓扑结构是如何在三维空间折叠成球状结构的。这项研究为阐明细胞质膜蛋白的拓扑结构测试了新的遗传策略。它还旨在分析非功能突变体，以确定跨膜片段的序列特征，使它们能够指导拓扑的建立，并识别跨膜片段在这一功能中与之相互作用的任何细胞成分。这项分析依赖于“感应器”蛋白质的使用，这些蛋白质的酶活性反映了它们在杂交蛋白质中附着的膜蛋白区域的正常细胞位置。这项研究使用在这个过程中有缺陷的突变体，分析了&gt；lac&gt；渗透酶的拓扑结构如何折叠成球状结构。这些突变体将被鉴定为不能运输乳糖的突变体的子集，或者通过改变在进化中被发现保守的氨基酸残基而在体外构建的突变体。

The aim of this research is to provide a better understanding of how membrane proteins acquire their final structures. The experiments analyze two >E.> >coli> cytoplasmic membrane proteins of simple and complex topological structures, the >trs> serine chemoreceptor and >lac> permease. The research aims to help elucidate both how the transmembrane topological structures of these proteins are generated and how the topological structures fold in three dimensions into globular structures. This research tests new genetic strategies for elucidating the topological structures of cytoplasmic membrane proteins. It also aims to analyze nonfunctional mutants to identify the sequence features of transmembrane segments that enable them to direct the establishment of topology, and to identify any cellular components with which the transmembrane segments interact in this function. The analysis relies on the use of "sensor" proteins whose enzymatic activities reflect the normal cellular location of the membrane protein domain to which they are attached in hybrid proteins. The research analyzes how the topological structure of >lac> permease folds into a globular structure using mutants that are defective in the process. Such mutants will be identified as a subset of mutants unable to transport lactose, or constructed >in> >vitro> by altering amino acid residues found to be conserved in evolution.