Related Experiment Videos
Ribosome-DnaK interactions in relation to protein folding
Jaydip Ghosh1, Arunima Basu, Saumen Pal
1Department of Biophysics, Molecular Biology and Genetics, University of Calcutta, 92 A. P. C. Road, India.
Molecular Microbiology
|June 7, 2003
Summary
Bacterial ribosomes, specifically the 50S subunit, can refold denatured proteins, including the chaperone DnaK. Ribosomes are essential for DnaK folding, and folded DnaK modulates ribosome protein folding activity.
Area of Science:
- Molecular Biology
- Protein Folding
- Ribosome Function
Background:
- Bacterial ribosomes and their 50S subunit possess protein refolding capabilities.
- This folding activity is primarily localized to domain V of the 23S ribosomal RNA.
Purpose of the Study:
- To investigate the ability of bacterial ribosomes to refold the denatured chaperone DnaK in vitro.
- To explore the in vivo implications for nascent DnaK polypeptide folding.
- To characterize the interaction between native DnaK and the 50S ribosomal subunit.
Main Methods:
- In vitro refolding assays using denatured DnaK and bacterial 50S ribosomal subunits.
- Stoichiometry and binding site analysis of native DnaK interaction with the 50S subunit.
- Assessment of the impact of DnaK binding on the protein folding activity of domain V.
Main Results:
- Bacterial ribosomes successfully refolded denatured DnaK in vitro.
- Native DnaK associated stably with the 50S subunit at a 1:1 stoichiometry.
- The binding site for native DnaK differs from domain V of 23S RNA.
- DnaK binding modulated domain V's folding activity, and denatured protein binding caused DnaK dissociation.
Conclusions:
- Bacterial ribosomes play a crucial role in the folding of the chaperone DnaK.
- DnaK folding appears to be ribosome-dependent.
- Folded DnaK can rebind to ribosomes to modulate their general protein folding activity.