Panaretou B, Prodromou C, Roe S M, O'Brien R, Ladbury J E, Piper P W, Pearl L H
Department of Biochemistry and Molecular Biology, University College London, Gower Street, London WC1E 6BT, UK.
EMBO J. 1998 Aug 17;17(16):4829-36. doi: 10.1093/emboj/17.16.4829.
Hsp90 is an abundant molecular chaperone essential to the establishment of many cellular regulation and signal transduction systems, but remains one of the least well described chaperones. The biochemical mechanism of protein folding by Hsp90 is poorly understood, and the direct involvement of ATP has been particularly contentious. Here we demonstrate in vitro an inherent ATPase activity in both yeast Hsp90 and the Escherichia coli homologue HtpG, which is sensitive to inhibition by the Hsp90-specific antibiotic geldanamycin. Mutations of residues implicated in ATP binding and hydrolysis by structural studies abolish this ATPase activity in vitro and disrupt Hsp90 function in vivo. These results show that Hsp90 is directly ATP dependent in vivo, and suggest an ATP-coupled chaperone cycle for Hsp90-mediated protein folding.
热休克蛋白90（Hsp90）是一种丰富的分子伴侣，对许多细胞调节和信号转导系统的建立至关重要，但仍是描述最少的伴侣蛋白之一。人们对Hsp90介导的蛋白质折叠的生化机制了解甚少，而ATP的直接参与一直存在特别大的争议。在此，我们在体外证明了酵母Hsp90和大肠杆菌同源物HtpG都具有内在的ATP酶活性，该活性对Hsp90特异性抗生素格尔德霉素的抑制敏感。通过结构研究表明，与ATP结合和水解相关的残基发生突变会在体外消除这种ATP酶活性，并在体内破坏Hsp90的功能。这些结果表明，Hsp90在体内直接依赖ATP，并提示了一个与ATP偶联的伴侣蛋白循环，用于Hsp90介导的蛋白质折叠。
