The oligomeric structure of GroEL/GroES is required for biologically significant chaperonin function in protein folding
| Autor: | Frank Weber, France Keppel, Costa Georgopoulos, Manajit K. Hayer-Hartl, F. Ulrich Hartl |
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| Rok vydání: | 1998 |
| Předmět: |
Models
Molecular Protein Folding GroES Protein Protein Conformation Recombinant Fusion Proteins Citrate (si)-Synthase macromolecular substances Biochemistry Chaperonin Malate Dehydrogenase Structural Biology Chaperonin 10 Escherichia coli Genetics Animals Sequence Deletion GroEL Protein biology Circular Dichroism Genetic Complementation Test Chaperonin 60 GroES GroEL Thiosulfate Sulfurtransferase Tetrahydrofolate Dehydrogenase enzymes and coenzymes (carbohydrates) Chaperone (protein) biological sciences Foldase health occupations Biophysics biology.protein bacteria Cattle Protein folding |
| Zdroj: | Nature Structural Biology. 5:977-985 |
| ISSN: | 1072-8368 |
| DOI: | 10.1038/2952 |
| Popis: | Two models are being considered for the mechanism of chaperonin-assisted protein folding in E. coli: (i) GroEL/GroES act primarily by enclosing substrate polypeptide in a folding cage in which aggregation is prevented during folding. (ii) GroEL mediates the repetitive unfolding of misfolded polypeptides, returning them onto a productive folding track. Both models are not mutually exclusive, but studies with the polypeptide-binding domain of GroEL have suggested that unfolding is the primary mechanism, enclosure being unnecessary. Here we investigate the capacity of the isolated apical polypeptide-binding domain to functionally replace the complete GroEL/GroES system. We show that the apical domain binds aggregation-sensitive polypeptides but cannot significantly assist their refolding in vitro and fails to replace the groEL gene or to complement defects of groEL mutants in vivo. A single-ring version of GroEL cannot substitute for GroEL. These results strongly support the view that sequestration of aggregation-prone intermediates in a folding cage is an important element of the chaperonin mechanism. |
| Databáze: | OpenAIRE |
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