Conditions for nucleotide-dependent GroES-GroEL interactions. GroEL sub(14)(GroES sub(7)) sub(2) is favored by an asymmetric distribution of nucleotides

A still unresolved question regarding the mechanism of chaperonin-assisted protein folding involves the stoichiometry of the GroEL-GroES complex. This is important, because the activities of the Escherichia coli chaperonin GroEL are modulated by the cochaperonin GroES. In this report, the binding of...

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Bibliographic Details
Published in:The Journal of biological chemistry 1997-10, Vol.272 (43), p.26999-27004
Main Authors: Gorovits, B M, Ybarra, J, Seale, J W, Horowitz, P M
Format: Article
Language:English
Online Access:Get full text
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Summary:A still unresolved question regarding the mechanism of chaperonin-assisted protein folding involves the stoichiometry of the GroEL-GroES complex. This is important, because the activities of the Escherichia coli chaperonin GroEL are modulated by the cochaperonin GroES. In this report, the binding of GroES to highly purified GroEL in the presence of ATP, ADP, and the nonhydrolyzable ATP analogue, 5'-adenylyl beta , gamma -imidodiphosphate (AMP-PNP), was investigated by using the fluorescence anisotropy of succinimidyl-1-pyrenebutyrate-labeled GroES. In the presence of Mg super(2+)-ATP and high [KCl] (10 mM), two GroES sub(7) rings bind per one GroEL sub(14). In contrast, in the presence of ADP or AMP-PNP only one molecule of oligomeric GroES can be tightly bound by GroEL. With AMP-PNP, binding of a small amount (
ISSN:0021-9258