Schmidt M, Rutkat K, Rachel R, Pfeifer G, Jaenicke R, Viitanen P, Lorimer G, Buchner J
Institut für Biophysik und Physikalische Biochemie, Universität Regensburg, Germany.
Science. 1994 Jul 29;265(5172):656-9. doi: 10.1126/science.7913554.
The particular structural arrangement of chaperonins probably contributes to their ability to assist in the folding of proteins. The interaction of the oligomeric bacterial chaperonin GroEL and its cochaperonin, GroES, in the presence of adenosine diphosphate (ADP) forms an asymmetric complex. However, in the presence of adenosine triphosphate (ATP) or its nonhydrolyzable analogs, symmetric complexes were found by electron microscopy and image analysis. The existence of symmetric chaperonin complexes is not predicted by current models of the functional cycle for GroE-mediated protein folding. Because complete folding of a nonnative substrate protein in the presence of GroEL and GroES only occurs in the presence of ATP, but not with ADP, the symmetric chaperonin complexes formed during the GroE cycle are proposed to be functionally significant.
伴侣蛋白独特的结构排列可能有助于它们协助蛋白质折叠的能力。寡聚细菌伴侣蛋白GroEL与其共伴侣蛋白GroES在二磷酸腺苷（ADP）存在的情况下相互作用，形成不对称复合物。然而，在三磷酸腺苷（ATP）或其不可水解类似物存在的情况下，通过电子显微镜和图像分析发现了对称复合物。目前GroE介导的蛋白质折叠功能循环模型并未预测到对称伴侣蛋白复合物的存在。由于非天然底物蛋白在GroEL和GroES存在的情况下只有在ATP存在时才会完全折叠，而在ADP存在时则不会，因此有人提出在GroE循环中形成的对称伴侣蛋白复合物具有功能意义。
