Symmetric complexes of GroE chaperonins as part of the functional cycle

Marion Schmidt, Kerstin Rutkat, Reinhard Rachel, Günter Pfeifer, Rainer Jaenicke, Paul Viitanen, George Lorimer, Johannes Buchner

Research output: Contribution to journalArticlepeer-review

188 Scopus citations


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.

Original languageEnglish
Pages (from-to)656-659
Number of pages4
Issue number5172
StatePublished - 1994
Externally publishedYes


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