Dynamics of substrate denaturation and translocation by the ClpXP degradation machine
Dynamics of substrate denaturation and translocation by the ClpXP degradation machine
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DOI：
10.1016/s1097-2765(00)80243-9
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发表时间：
2000-04-01
期刊：
影响因子：
16
通讯作者：
Baker, TA
中科院分区：
文献类型：
--
作者：
Kim, YI;Burton, RE;Baker, TA
ClpXP是由ClpX atp酶（Clp/Hsp100重塑酶家族成员）和clop肽酶组成的蛋白质机器。在这里，ClpX和ClpXP被证明可以催化用ssrA降解标签修饰的GFP变性。ClpX将这种变性蛋白易位到ClpP的蛋白水解腔中，当蛋白水解被阻断时，还会催化从ClpP中释放变性GFP-ssrA，这一反应需要ATP和额外的底物。动力学实验表明，多个反应步骤需要ClpX和ClpP之间的协同作用，变性是降解过程中的速率决定步骤。这些对ClpXP机制的见解解释了它如何以一种对标记蛋白高度特异性的方式执行有效降解，而不管它们的内在稳定性如何。
ClpXP is a protein machine composed of the ClpX ATPase, a member of the Clp/Hsp100 family of remodeling enzymes, and the clop peptidase. Here, ClpX and ClpXP are shown to catalyze denaturation of GFP modified with an ssrA degradation tag. ClpX translocates this denatured protein into the proteolytic chamber of ClpP and, when proteolysis is blocked, also catalyzes release of denatured GFP-ssrA from ClpP in a reaction that requires ATP and additional substrate. Kinetic experiments reveal that multiple reaction steps require collaboration between ClpX and ClpP and that denaturation is the rate-determining step in degradation. These insights into the mechanism of ClpXP explain how it executes efficient degradation in a manner that is highly specific for tagged proteins, irrespective of their intrinsic stabilities.