期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2003
卷号：100
期号：24
页码：13797-13802
DOI：10.1073/pnas.2333925100
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The reaction cycle of the double-ring chaperonin GroEL is driven by ATP binding that takes place with positive cooperativity within each seven-membered ring and negative cooperativity between rings. The positive cooperativity within rings is due to ATP binding-induced conformational changes that are fully concerted. Herein, it is shown that the mutation Asp-155 [->] Ala leads to an ATP-induced break in intra-ring and inter-ring symmetry. Electron microscopy analysis of single-ring GroEL particles containing the Asp-155 [->] Ala mutation shows that the break in intra-ring symmetry is due to stabilization of allosteric intermediates such as one in which three subunits have switched their conformation while the other four have not. Our results show that eliminating an intra-subunit interaction between Asp-155 and Arg-395 results in conversion of the allosteric switch of GroEL from concerted to sequential, thus demonstrating that its allosteric behavior arises from coupled tertiary conformational changes.
关键词：allostery ; chaperonin ; protein folding ; cooperativity ; electron microscopy
