A specificity-enhancing factor for the ClpXP degradation machine
A specificity-enhancing factor for the ClpXP degradation machine
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DOI：
10.1126/science.289.5488.2354
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发表时间：
2000-09-29
期刊：
影响因子：
56.9
通讯作者：
Baker, TA
中科院分区：
文献类型：
--
作者：
Levchenko, I;Seidel, M;Baker, TA
阻碍细菌蛋白质合成的事件激活了ssrA标记机制，导致11个残基的翻译和添加到新生链羧基末端。这个由ssrA编码的多肽标签标记了不完整的蛋白质，供能量依赖的ClpXP蛋白酶降解。在这里，发现了一种核糖体相关蛋白SspB，它能特异性地与ssrA标记的蛋白质结合，并增强ClpXP对这些蛋白质的识别。带有sspB突变的细胞在降解ssrA标记的蛋白质方面存在缺陷，表明SspB是控制底物选择的ClpXP的特异性增强因子。
Events that stall bacterial protein, synthesis activate the ssrA-tagging machinery, resulting in resumption of translation and addition of an 11-residue peptide to the carboxyl terminus of the nascent chain. This ssrA-encoded peptide tag marks the incomplete protein for degradation by the energy-dependent ClpXP protease. Here, a ribosome-associated protein, SspB, was found to bind specifically to ssrA-tagged proteins and to enhance recognition of these proteins by ClpXP. Cells with an sspB mutation are defective in degrading ssrA-tagged proteins, demonstrating that SspB is a specificity-enhancing factor for ClpXP that controls substrate choice.