The chaperonin GroEL binds nonnative proteins too large to fit inside the productive GroEL-GroES cis cavity, but whether and how it assists their folding has remained unanswered. We have examined yeast mitochondrial aconitase, an 82 kDa monomeric Fe(4)S(4) cluster-containing enzyme, observed to aggregate in chaperonin-deficient mitochondria. We observed that aconitase folding both in vivo and in vitro requires both GroEL and GroES, and proceeds via multiple rounds of binding and release. Unlike the folding of smaller substrates, however, this mechanism does not involve cis encapsulation but, rather, requires GroES binding to the trans ring to release nonnative substrate, which likely folds in solution. Following the phase of ATP/GroES-dependent refolding, GroEL stably bound apoaconitase, releasing active holoenzyme upon Fe(4)S(4) cofactor formation, independent of ATP and GroES.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/s0092-8674(01)00523-2 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
A biochemical screen for GroEL/GroES inhibitors.
Bioorg Med Chem Lett
February 2014
The University of Arizona, College of Pharmacy, Department of Pharmacology and Toxicology, 1703 E. Mabel St., PO Box 210207, Tucson, AZ 85721-0207, USA. Electronic address:
High-throughput screening of 700,000 small molecules has identified 235 inhibitors of the GroEL/GroES-mediated refolding cycle. Dose-response analysis of a subset of these hits revealed that 21 compounds are potent inhibitors of GroEL/GroES-mediated refolding (IC50 <10 μM). The screening results presented herein represent the first steps in a broader aim of developing molecular probes to study chaperonin biochemistry and physiology.
View Article and Find Full Text PDFChaperonin chamber accelerates protein folding through passive action of preventing aggregation.
Proc Natl Acad Sci U S A
November 2008
Howard Hughes Medical Institute and Department of Genetics, Yale School of Medicine, Boyer Center, New Haven, CT 06510, USA.
The original experiments reconstituting GroEL-GroES-mediated protein folding were carried out under "nonpermissive" conditions, where the chaperonin system was absolutely required and substrate proteins could not achieve the native state if diluted directly from denaturant into solution. Under "permissive" conditions, however, employing lower substrate concentration and lower temperature, some substrate proteins can be refolded both by the chaperonin system and while free in solution. For several of these, the protein refolds more rapidly inside the GroEL-GroES cis chamber than free in solution, suggesting that the chamber may have an active role in assisting protein folding.
View Article and Find Full Text PDFGroEL-GroES-mediated protein folding.
Chem Rev
May 2006
Department of Genetics and Howard Hughes Medical Institute, Yale School of Medicine, Boyer Center, 295 Congress Avenue, New Haven, Connecticut 06510, USA.
Folding with and without encapsulation by cis- and trans-only GroEL-GroES complexes.
EMBO J
July 2003
Howard Hughes Medical Institute and Department of Genetics, Yale School of Medicine, Boyer Center, 295 Congress Avenue, New Haven, CT 06510, USA.
Although a cis mechanism of GroEL-mediated protein folding, occurring inside a hydrophilic chamber encapsulated by the co-chaperonin GroES, has been well documented, recently the GroEL-GroES-mediated folding of aconitase, a large protein (82 kDa) that could not be encapsulated, was described. This process required GroES binding to the ring opposite the polypeptide (trans) to drive release and productive folding. Here, we have evaluated this mechanism further using trans-only complexes in which GroES is closely tethered to one of the two GroEL rings, blocking polypeptide binding by that ring.
View Article and Find Full Text PDFAllostery and protein substrate conformational change during GroEL/GroES-mediated protein folding.
Adv Protein Chem
August 2002
Department of Crystallography, Birkbeck College London, Malet Street, London, WC1E 7HX, UK.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!