Structural basis for intersubunit signaling in a protein disaggregating machine
Structural basis for intersubunit signaling in a protein disaggregating machine
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DOI：
10.1073/pnas.1207040109
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发表时间：
2012-07-31
影响因子：
11.1
通讯作者：
Tsai, Francis T. F.
中科院分区：
文献类型：
--
作者：
Biter, Amadeo B.;Lee, Sukyeong;Tsai, Francis T. F.
ClpB是一种成环的ATP依赖性蛋白解聚酶，与同源Hsp70系统合作从聚集体中回收功能蛋白。ClpB如何利用ATP结合和水解的能量来促进先前聚集的、应激损伤的蛋白质的机械展开仍不清楚。在这里，我们目前的晶体结构的ClpB D2结构域的核苷酸结合和无状态，和安装cryoEM结构的D2六聚体环，这提供了一个结构的理解ATP的功率冲程，驱动蛋白质易位通过ClpB六聚体。我们表明，底物转运孔环的构象耦合到顺式亚基的核苷酸状态，这是通过保守的，但结构不同的亚基间信号通路常见的不同AAA+机器传输到相邻的亚基。此外，我们发现，一个工程化的，二硫键交联的ClpB六聚体是完全功能的生化，这表明ClpB去寡聚化是不需要蛋白质解聚。
ClpB is a ring-forming, ATP-dependent protein disaggregase that cooperates with the cognate Hsp70 system to recover functional protein from aggregates. How ClpB harnesses the energy of ATP binding and hydrolysis to facilitate the mechanical unfolding of previously aggregated, stress-damaged proteins remains unclear. Here, we present crystal structures of the ClpB D2 domain in the nucleotide-bound and -free states, and the fitted cryoEM structure of the D2 hexamer ring, which provide a structural understanding of the ATP power stroke that drives protein translocation through the ClpB hexamer. We demonstrate that the conformation of the substrate-translocating pore loop is coupled to the nucleotide state of the cis subunit, which is transmitted to the neighboring subunit via a conserved but structurally distinct intersubunit-signaling pathway common to diverse AAA+ machines. Furthermore, we found that an engineered, disulfide cross-linked ClpB hexamer is fully functional biochemically, suggesting that ClpB deoligomerization is not required for protein disaggregation.