Porankiewicz J, Wang J, Clarke A K
Department of Plant Physiology, University of Umeå, Umeå S-901 87, Sweden.
Mol Microbiol. 1999 May;32(3):449-58. doi: 10.1046/j.1365-2958.1999.01357.x.
Proteolysis functions as a precise regulatory mechanism for a broad spectrum of cellular processes. Such control impacts not only on the stability of key metabolic enzymes but also on the effective removal of terminally damaged polypeptides. Much of this directed protein turnover is performed by proteases that require ATP and, of those in bacteria, the Clp protease from Escherichia coli is one of the best characterized to date. The Clp holoenzyme consists of two adjacent heptameric rings of the proteolytic subunit known as ClpP, which are flanked by a hexameric ring of a regulatory subunit from the Clp/Hsp100 chaperone family at one or both ends. The recently resolved three-dimensional structure of the E. coli ClpP protein has provided new insights into its interaction with the regulatory/chaperone subunits. In addition, an increasing number of studies over the last few years have recognized the added complexity and functional importance of ClpP proteins in other eubacteria and, in particular, in photosynthetic organisms ranging from cyanobacteria to higher plants. The goal of this review is to summarize these recent findings and to highlight those areas that remain unresolved.
蛋白质水解作为广泛细胞过程的精确调控机制发挥作用。这种调控不仅影响关键代谢酶的稳定性，还影响对最终受损多肽的有效清除。这种定向的蛋白质周转很大程度上由需要ATP的蛋白酶完成，在细菌中，来自大肠杆菌的Clp蛋白酶是迄今为止特征最明确的之一。Clp全酶由两个相邻的蛋白水解亚基ClpP的七聚体环组成，在一端或两端由来自Clp/Hsp100伴侣家族的调节亚基的六聚体环侧翼。最近解析的大肠杆菌ClpP蛋白的三维结构为其与调节/伴侣亚基的相互作用提供了新见解。此外，在过去几年中，越来越多的研究认识到ClpP蛋白在其他真细菌中，特别是在从蓝细菌到高等植物的光合生物中的复杂性增加和功能重要性。本综述的目的是总结这些最新发现，并突出那些仍未解决的领域。
