Lack of a robust unfoldase activity confers a unique level of substrate specificity to the universal AAA protease FtsH
Lack of a robust unfoldase activity confers a unique level of substrate specificity to the universal AAA protease FtsH
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DOI：
10.1016/s1097-2765(03)00068-6
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发表时间：
2003-03-01
期刊：
影响因子：
16
通讯作者：
Gross, CA
中科院分区：
文献类型：
--
作者：
Herman, C;Prakash, S;Gross, CA
FtsH是AAA蛋白家族的一员，是原核生物中唯一普遍保守的膜atp依赖蛋白酶，也是大肠杆菌中唯一必需的atp依赖蛋白酶。我们研究了FtsH的降解机制。其他被充分研究的依赖ATP的蛋白酶利用ATP展开它们的底物。相比之下，体外和体内研究都表明，只有当底物是一种内在热力学稳定性较低的蛋白质时，FtsH才能有效地降解。由于FtsH缺乏强大的展开酶活性，它能够使用底物的蛋白质折叠状态作为降解的标准。这一特征可能是其在细胞中的作用的关键，并解释了其在原核生物中的普遍分布。
FtsH, a member of the AAA family of proteins, is the only membrane ATP-dependent protease universally conserved in prokaryotes, and the only essential ATP-dependent protease in Escherichia coli. We investigated the mechanism of degradation by FtsH. Other well-studied ATP-dependent proteases use ATP to unfold their substrates. In contrast, both in vitro and in vivo studies indicate that degradation by FtsH occurs efficiently only when the substrate is a protein of low intrinsic thermodynamic stability. Because FtsH lacks robust unfoldase activity, it is able to use the protein folding state of substrates as a criterion for degradation. This feature may be key to its role in the cell and account for its ubiquitous distribution among prokaryotic organisms.