ATP binding to nucleotide binding domain (NBD)1 of the ClpB chaperone induces motion of the long coiled-coil, stabilizes the hexamer, and activates NBD2
ATP binding to nucleotide binding domain (NBD)1 of the ClpB chaperone induces motion of the long coiled-coil, stabilizes the hexamer, and activates NBD2
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DOI：
10.1074/jbc.m414623200
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发表时间：
2005-07-01
影响因子：
4.8
通讯作者：
Yoshida, M
中科院分区：
文献类型：
--
作者：
Watanabe, Y;Takano, M;Yoshida, M
分子伴侣ClpB可以与其他分子伴侣合作将热损伤蛋白从聚集状态中拯救出来。它有两个核苷酸结合结构域（NBD 1和NBD 2），并以依赖于ATP与NBD 1结合的方式形成六聚体环。在两个NBD都被核苷酸填充的ClpB的晶体结构中，两个NBD之间的接头形成85埃长的卷曲螺旋，其在六聚体的外部延伸并倾向于NBD 1。为了探测卷曲螺旋的可能运动，我们通过使用具有缺陷NBD 1或NBD 2的突变体测试了标记试剂的可及性、标记染料的荧光变化以及卷曲螺旋与NBD 1之间的交联。结果表明，卷曲螺旋或多或少平行于ClpB的主体，在核苷酸的情况下，ATP结合NBD 1使其倾斜的位置，如在晶体结构中看到的。该运动导致ClpB的六聚体形式的稳定化和促进NBD 2处的ATP水解。
The molecular chaperone ClpB can rescue the heat-damaged proteins from an aggregated state in cooperation with other chaperones. It has two nucleotide binding domains (NBD1 and NBD2) and forms a hexamer ring in a manner dependent on ATP binding to NBD1. In the crystal structure of ClpB with both NBDs filled by nucleotides, the linker between two NBDs forms an 85-angstrom-long coiled-coil that extends on the outside of the hexamer and leans to NBD1. To probe the possible motion of the coiled-coil, we tested the accessibility of a labeling reagent, fluorescence change of a labeled dye, and cross-linking between the coiled-coil and NBD1 by using the mutants with defective NBD1 or NBD2. The results suggest that the coiled-coil is more or less parallel to the main body of ClpB in the absence of nucleotide and that ATP binding to NBD1 brings it to the leaning position as seen in the crystal structure. This motion results in stabilization of the hexamer form of ClpB and promotion of ATP hydrolysis at NBD2.