Analysis of GroE-assisted folding under nonpermissive conditions.
The molecular chaperones GroEL and GroES facilitate protein folding in an ATP-dependent manner under conditions where no spontaneous folding occurs. It has remained unknown whether GroE achieves this by a passive sequestration of protein inside the GroE cavity or by changing the folding pathway of a protein. Here we used citrate synthase, a well studied model substrate, to discriminate between these possibilities. We demonstrate that GroE maintains unfolding intermediates in a state that allows productive folding under nonpermissive conditions. During encapsulation of non-native protein inside GroEL.GroES complexes, a folding reaction takes place, generating association-competent monomeric intermediates that are no longer recognized by GroEL. Thus, GroE shifts folding intermediates to a productive folding pathway under heat shock conditions where even the native protein unfolds in the absence of GroE.
Grallert
H
H
Institut für Organische Chemie and Biochemie, Technische Universität München, Lichtenbergstrasse 4, 85747 Garching, Germany.
Buchner
J
J
D018835:Chaperonin 10 / Q000378:metabolism*; D018834:Chaperonin 60 / Q000378:metabolism*; D002950:Citrate (si)-Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D006358:Hot Temperature; D007700:Kinetics; D011489:Protein Denaturation; D017510:Protein Folding; D011994:Recombinant Proteins / Q000378:metabolism
D018835:Chaperonin 10; D018834:Chaperonin 60; D011994:Recombinant Proteins; D002950:Citrate (si)-Synthase