Crystal Structures of a Group II Chaperonin Reveal the Open and Closed States Associated with the Protein Folding Cycle
Crystal Structures of a Group II Chaperonin Reveal the Open and Closed States Associated with the Protein Folding Cycle
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DOI：
10.1074/jbc.m110.125344
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发表时间：
2010-09-03
影响因子：
4.8
通讯作者：
Adams, Paul D.
中科院分区：
文献类型：
--
作者：
Pereira, Jose H.;Ralston, Corie Y.;Adams, Paul D.
伴侣蛋白是由两个堆叠的多亚基环组成的大型蛋白质复合物，以atp依赖的方式打开和关闭，为蛋白质折叠创造一个受保护的环境。在这里，我们描述了开放构象的第一个II族伴侣蛋白的晶体结构。我们已经从马里帕鲁迪甲烷球菌中获得了肽受体（开放）状态和蛋白质折叠（关闭）状态的古细菌伴侣蛋白结构。与I族伴侣蛋白不同，I族伴侣蛋白的赤道结构域在开放和封闭状态之间具有相似的构象，最大的运动发生在中间和顶端结构域，而古细菌伴侣蛋白亚基的三个结构域作为一个单一的刚体重新定向。从打开状态到关闭状态的大旋转导致折叠室体积减少65%，并在笼内形成高度亲水的表面。这些结果表明，与I组伴侣蛋白相比，II组伴侣蛋白具有完全不同的关闭机制。
Chaperonins are large protein complexes consisting of two stacked multisubunit rings, which open and close in an ATP-dependent manner to create a protected environment for protein folding. Here, we describe the first crystal structure of a group II chaperonin in an open conformation. We have obtained structures of the archaeal chaperonin from Methanococcus maripaludis in both a peptide acceptor (open) state and a protein folding (closed) state. In contrast with group I chaperonins, in which the equatorial domains share a similar conformation between the open and closed states and the largest motions occurs at the intermediate and apical domains, the three domains of the archaeal chaperonin subunit reorient as a single rigid body. The large rotation observed from the open state to the closed state results in a 65% decrease of the folding chamber volume and creates a highly hydrophilic surface inside the cage. These results suggest a completely distinct closing mechanism in the group II chaperonins as compared with the group I chaperonins.