ClpX(P) 产生机械力来展开和转移其蛋白质基质
Rodrigo A Maillard1, Gheorghe Chistol, Maya Sen
1Jason L. Choy Laboratory of Single-Molecule Biophysics, University of California, Berkeley, 94720, USA.
Cell
|May 3, 2011
概括
像ClpX这样的AAA ((+) 解酶使用ATP机械地解蛋白质. ClpX unfoldase,特别是与 ClpP 酶一起,可以有效地变形和转移聚.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 结构生物学 结构生物学
背景情况:
- AAA(+) 解酶是依赖ATP的分子机器,可以解和转移蛋白质.
- ClpX和ClpP形成一个复合体 (ClpXP),对大肠杆菌中蛋白质降解至关重要.
研究的目的:
- 直接观察由ClpX unfoldase引发的机械,强力诱导的蛋白质展开.
- 研究ATP水解的作用和与ClpP在展开和转位过程中的相互作用.
主要方法:
- 单分子力光谱法用于测量因力诱导的蛋白质展开.
- 通过ClpX中心孔的多转位的观察.
- 对转位速度和步骤大小的分析.
主要成果:
- ClpX 机械地展开蛋白质,转位速度取决于力,最大达到 80 aa/s 接近零的力,并在 ~ 20 pN 停止.
- ClpX 显示的步骤大小为 1,2,或 3 nm,表示 1 nm 的基本步骤和子单位间的协调.
- 结合ClpP可降低ClpX的滑动概率,提高展开效率.
- 通过一个短暂的中间体,ClpXP复合物通过合作方式解开GFP.
结论:
- ClpX利用ATP水解来产生用于蛋白质展开和转移的机械力.
- 与单独的ClpXP相比,ClpXP复合体在蛋白质展开方面表现出更高的效率.
- 这些发现提供了关于机械蛋白质通过AAA (((+) unfoldases展开的机制的见解.
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