Genetic Competence Apparatus of Bacillus Subtilis

细菌的自然转化是指外源DNA的摄取和整合。枯草芽孢杆菌 当处于被称为感受态的生理状态时，可以被外源DNA转化。主管 细胞能够结合双链DNA，在细胞表面上将DNA片段化，并转运单链DNA。 穿过细胞膜。我们的长期目标是了解这些过程， 分子水平这项提议探索了已知参与结合的蛋白质的特定作用， 转化DNA的加工和运输（内化）。这些蛋白质中的几种（七种 comG基因产物，ComC和ComEA）是DNA与细胞表面结合所必需的， 其它的（ComEC、ComFA和ComEA）是DNA跨细胞膜转运所必需的。的 拟议的工作将探讨这些蛋白质之间的相互作用和巯基二硫化物的作用， 氧化还原酶BdbD和BdbC在这些蛋白质的折叠和DNA摄取的组装中的作用 设备.新发现的高阶ComGC复合物的形成和性质将是 将阐明其在DNA结合中的作用。假定的膜通道的结构 蛋白质ComEC和转运蛋白ATP酶ComFA的体外生物化学活性将被 特征进一步。细胞中这些不同蛋白质的量将被确定。几个新 将研究鉴定的转化蛋白。最后，将尝试开发一个 基于囊泡的体外DNA转运系统。

Natural transformation in bacteria refers to the uptake and integration of exogenous DNA. Bacillus subtilis can be transformed by exogenous DNA when in a physiological state known as competence. Competent cells are able to bind double stranded DNA, fragment the DNA on the cell surface and transport a single strand across the cell membrane. Our long-term objective is to understand these processes on the molecular evel. This proposal explores the specific roles of proteins known to participate in the binding, processing and transport (internalization) of transforming DNA. Several of these proteins (the seven comG gene products, ComC and ComEA) are needed for the binding of DNA to the cell surface while others (ComEC, ComFA and ComEA) are required for transport of DNA across the cell membrane. The proposed work will explore interactions among these proteins and the role of the thiol-disulfide oxidoreductases BdbD and BdbC in the folding of these proteins and in the assembly of the DNA uptake apparatus. The formation and properties of a newly identified higher order ComGC complex will be elucidated and its role in DNA binding will be examined. The structure of the putative membrane channel protein ComEC and the in vitro biochemical activities of the transporter ATPase ComFA will be characterized further. The amounts of these various proteins in the cell will be determined. Several newly identifed transformation proteins will be studied. Finally an attempt will be made to develop a vesicle-based in vitro DNA transport system.