Double mutant MBP refolds at same rate in free solution as inside the GroEL/GroES chaperonin chamber when aggregation in free solution is prevented
| Autor: | Arthur L. Horwich, Navneet K. Tyagi, Wayne A. Fenton, Ashok A. Deniz |
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| Rok vydání: | 2011 |
| Předmět: |
Protein Folding
Chaperonins Light GroES Kinetics Biophysics Biochemistry Free solution GroEL Article Chaperonin Aggregation Dynamic light scattering DM-MBP Structural Biology MBP Genetics Chaperonin 10 Humans Scattering Radiation Molecular Biology Chemistry Substrate (chemistry) Myelin Basic Protein Cell Biology Chaperonin 60 Folding (chemistry) Solutions Crystallography bacteria Mutant Proteins |
| Zdroj: | FEBS letters. 585(12) |
| ISSN: | 1873-3468 |
| Popis: | Under “permissive” conditions at 25°C, the chaperonin substrate protein DM-MBP refolds 5–10 times more rapidly in the GroEL/GroES folding chamber than in free solution. This has been suggested to indicate that the chaperonin accelerates polypeptide folding by entropic effects of close confinement. Here, using native-purified DM-MBP, we show that the different rates of refolding are due to reversible aggregation of DM-MBP while folding free in solution, slowing its kinetics of renaturation: the protein exhibited concentration-dependent refolding in solution, with aggregation directly observed by dynamic light scattering. When refolded in chloride-free buffer, however, dynamic light scattering was eliminated, refolding became concentration-independent, and the rate of refolding became the same as that in GroEL/GroES. The GroEL/GroES chamber thus appears to function passively toward DM-MBP. |
| Databáze: | OpenAIRE |
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