MODE OF ACTION OF A BACTERIAL FUNCTION INVOLVED IN CELL GROWTH CONTROL

我们一直在研究蛋白质降解在调节 通过对蛋白酶的研究来控制细胞生长 在大肠杆菌中依赖三磷酸腺苷的蛋白质分解。Lon蛋白酶降解RCSA，a 荚膜多糖合成的正调控因子和细胞株Sula 分裂抑制因子。我们已经证明了RCSA在细胞内相互作用 与另一种正向调节剂RCSB一起促进高效胶囊 综合。CLP蛋白酶是第二种主要的依赖于ATP的蛋白酶， 含有一个具有ATPase活性的大亚基ClpA；这个亚基已经 在其他原核细胞和真核细胞中都很保守。这个 较小的亚基ClpP包含蛋白酶的活性部位，以及 经历自我处理的反应。小的亚基也是保守的 在许多细胞中。CLP蛋白水解酶的结构和一般组织 表明它与真核细胞的能量依赖有许多相似之处 降解泛素结合蛋白的蛋白酶。阿尔卑斯山，三分之一 依赖能量的蛋白酶活性，在以下情况下可替代Lon 过度生产，由一组紧密相连的基因和一个阳性基因组成 调整器。在研究细菌细胞生长的另一种方法中 对照、在细菌分离方面可能有缺陷的突变体 已经对染色体进行了选择、定位和鉴定。

We have been studying the role that protein degradation plays in regulating cell growth control, through the study of the proteases which carry out ATP-dependent proteolysis in E. coli. The Lon protease degrades RcsA, a positive regulator of capsular polysaccharide synthesis, and SulA, a cell division inhibitor. We have demonstrated that RcsA interacts in the cell with another positive regulator, RcsB to promote efficient capsule synthesis. The Clp protease, a second major ATP-dependent protease, contains a large subunit, ClpA, with ATPase activity; this subunit has been well conserved in both other prokaryotic cells and eukaryotic cells. The smaller subunit, ClpP, contains the active site of the protease, and undergoes a self-processing reaction. The small subunit is also conserved in many cells. The structure and general organization of the Clp protease suggests that it has many similarities to the eukaryotic energy-dependent proteases which degrade ubiquitin-conjugated proteins. Alp, a third energy-dependent protease activity, which can substitute for Lon when overproduced, consists of a set of closely linked genes and a positive regulator. In another approach to the study of bacterial cell growth control, mutants which may be defective in partition of the bacterial chromosome have been selected, mapped and characterized.