Conversion of the allosteric transition of GroEL from concerted to sequential by the single mutation Asp-155 approaches limit of Ala

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...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 2003-11, Vol.100 (24), p.13797
Main Authors: Danziger, Oded, Rivenzon-Segal, Dalia, Wolf, Sharon G, Horovitz, Amnon
Format: Article
Language:English
Subjects:
Biochemistry
Protein folding
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Summary: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. [PUBLICATION ABSTRACT]
ISSN:0027-8424
1091-6490