A tightly regulated molecular toggle controls AAA plus disaggregase
A tightly regulated molecular toggle controls AAA plus disaggregase
复制标题
DOI：
10.1038/nsmb.2441
复制
发表时间：
2012-12-01
影响因子：
16.8
通讯作者：
Bukau, Bernd
中科院分区：
文献类型：
--
作者：
Oguchi, Yuki;Kummer, Eva;Bukau, Bernd
成环 AAA+ 蛋白 ClpB 与 DnaK 伴侣系统配合，在大肠杆菌中重新折叠聚集蛋白。 M 结构域是一种 ClpB 特异性卷曲螺旋结构，具有两个翼（基序 1 和基序 2），对于解聚至关重要，但 M 结构域在 ClpB 六聚体中的定位和机制作用仍未解决。我们发现 M 结构域位于 ClpB 环表面，两个 M 结构域基序均与第一个 ATP 酶结构域 (AAA-1) 接触。两个翅膀都有助于维持受抑制的 ClpB 活动状态。基序 2 在分子内与 AAA-1 对接以调节 ClpB 解折叠能力，基序 1 与邻近的 AAA-1 结构域接触。稳定基序 2 对接的突变会抑制 ClpB，而不稳定会导致 ClpB 活性去抑制，具有更大的去折叠能力，在体内具有毒性。我们的结果强调了严格 ClpB 活性控制的重要本质，并阐明了受调节的 M 结构域切换控制机制。
The ring-forming AAA+ protein ClpB cooperates with the DnaK chaperone system to refold aggregated proteins in Escherichia coli. The M domain, a ClpB-specific coiled-coil structure with two wings, motif 1 and motif 2, is essential to disaggregation, but the positioning and mechanistic role of M domains in ClpB hexamers remain unresolved. We show that M domains nestle at the ClpB ring surface, with both M-domain motifs contacting the first ATPase domain (AAA-1). Both wings contribute to maintaining a repressed ClpB activity state. Motif 2 docks intramolecularly to AAA-1 to regulate ClpB unfolding power, and motif 1 contacts a neighboring AAA-1 domain. Mutations that stabilize motif 2 docking repress ClpB, whereas destabilization leads to derepressed ClpB activity with greater unfolding power that is toxic in vivo. Our results underline the vital nature of tight ClpB activity control and elucidate a regulated M-domain toggle control mechanism.