STRUCTURE & INTERACTIONS OF THE CLP PROTEASE SYSTEM: FOLDING & DEGRADATION

CLP蛋白水解酶系统是蛋白质中的重要组成部分 细菌和植物体内的新陈代谢。它由 ClpP蛋白水解酶，它本身对大多数 生理底物，以及ClpA家族的ATPase，它们 将衬底提交给CIPP。CIP系统发挥着重要作用 细菌和植物中依赖于ATP的蛋白质周转，但可能 也起到了方便运输、折叠和 一些蛋白质的激活。因此，该系统可以表示 细胞折叠途径中的一个重要决定点 退化。我们正在研究ClpP和ClpA的三名成员 使用野生型的大肠杆菌ATPase家族(ClpA、ClpB和ClpX) 以及从克隆基因中表达的工程蛋白。以前我们 证实了大肠杆菌ClpP是一个21.5 kDa亚基的十四聚体。 最近，我们已经生长出衍射率为2.2a的ClpP晶体 决议。我们建议确定它的三维结构。 ClpP的高分辨率结构可能为以下方面提供重要线索： A)丝氨酸蛋白酶作用机制的细节，b)线索 ClpP的变构调节的性质，以及c)帮助 理解CIP机制中对ATP的要求 蛋白酶。

The Clp protease system is an important element in protein metabolism in both bacteria and plant plastids. It consists of the ClpP protease, which by itself is probably inactive on most physiological substrates, and the ClpA family of ATPases, which present substrates to CIpP. The CIp system plays a major role ATP-dependent turnover of proteins in bacteria and plants, but may also play a role in facilitating the transport, folding, and activation of some proteins. This system may, therefore, repre sent an important decision point in the cellular pathway of folding and degradation. We are studying ClpP and three members of the ClpA family of ATPases from E. coli (ClpA, ClpB, and ClpX) using wild type and engineered proteins expressed from cloned genes. Previously we demonstrated that E. coli ClpP is a tetradecamer of 21.5kDa subunits'. Recently, we have grown crystals of ClpP that diffract to 2.2A resolution. We propose to determine its three-dimensional structure. A high resolution str ucture of ClpP may provide important clues into: a) the details of mechanism of action of serine proteases, b) clues to the nature of the allosteric regulation of ClpP, and c) aid in understanding the requirement of ATP in the mechanism of the CIp protease.