Chaperonin-mediated protein folding: GroES binds to one end of the GroEL cylinder, which accommodates the protein substrate within its central cavity Journal Article


Authors: Langer, T.; Pfeifer, G.; Martin, J.; Baumeister, W.; Hartl, F. U.
Article Title: Chaperonin-mediated protein folding: GroES binds to one end of the GroEL cylinder, which accommodates the protein substrate within its central cavity
Abstract: The mechanism of GroEL (chaperonin)-mediated protein folding is only partially understood. We have analysed structural and functional properties of the interaction between GroEL and the co-chaperonin GroES. The stoichiometry of the GroEL 14mer and the GroES 7mer in the functional holo-chaperonin is 1:1. GroES protects half of the GroEL subunits from proteolytic truncation of the approximately 50 C-terminal residues. Removal of this region results in an inhibition of the GroEL ATPase, mimicking the effect of GroES on full-length GroEL. Image analysis of electron micrographs revealed that GroES binding triggers conspicuous conformational changes both in the GroES adjacent end and at the opposite end of the GroEL cylinder. This apparently prohibits the association of a second GroES oligomer. Addition of denatured polypeptide leads to the appearance of irregularly shaped, stain-excluding masses within the GroEL double-ring, which are larger with bound alcohol oxidase (75 kDa) than with rhodanese (35 kDa). We conclude that the functional complex of GroEL and GroES is characterized by asymmetrical binding of GroES to one end of the GroEL cylinder and suggest that binding of the substrate protein occurs within the central cavity of GroEL.
Keywords: protein folding; mitochondria; precursor; atp hydrolysis; reconstitution; identification; escherichia-coli; molecular chaperones; purification; aggregation; groel; chaperonin; groes; carboxylase
Journal Title: EMBO Journal
Volume: 11
Issue: 13
ISSN: 0261-4189
Publisher: Wiley Blackwell  
Date Published: 1992-12-01
Start Page: 4757
End Page: 4765
Language: English
ACCESSION: WOS:A1992KC83700010
DOI: 10.1002/j.1460-2075.1992.tb05581.x
PROVIDER: wos
PMCID: PMC556951
PUBMED: 1361169
Notes: Source: Wos
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  1. F. Ulrich Hartl
    75 Hartl
  2. Jörg Martin
    12 Martin