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Mechanism and Rates of Exchange of L7/L12 between Ribosomes and the Effects of Binding EF-G
- Source :
- ACS Chemical Biology; Vol 7, ACS Chemical Biology, ACS Chemical Biology, American Chemical Society, 2012, 7 (6), pp.1120-1127. ⟨10.1021/cb300081s⟩
- Publication Year :
- 2012
- Publisher :
- American Chemical Society, 2012.
-
Abstract
- The ribosomal stalk complex binds and recruits translation factors to the ribosome during protein biosynthesis. In Escherichia coli the stalk is composed of protein L10 and four copies of L7/L12. Despite the crucial role of the stalk, mechanistic details of L7/L12 subunit exchange are not established. By incubating isotopically labeled intact ribosomes with their unlabeled counterparts we monitored the exchange of the labile stalk proteins by recording mass spectra as a function of time. On the basis of kinetic analysis, we proposed a mechanism whereby exchange proceeds via L7/L12 monomers and dimers. We also compared exchange of L7/L12 from free ribosomes with exchange from ribosomes in complex with elongation factor G (EF-G), trapped in the posttranslocational state by fusidic acid. Results showed that binding of EF-G reduces the L7/L12 exchange reaction of monomers by ~27% and of dimers by ~47% compared with exchange from free ribosomes. This is consistent with a model in which binding of EF-G does not modify interactions between the L7/L12 monomers but rather one of the four monomers, and as a result one of the two dimers, become anchored to the ribosome-EF-G complex preventing their free exchange. Overall therefore our results not only provide mechanistic insight into the exchange of L7/L12 monomers and dimers and the effects of EF-G binding but also have implications for modulating stability in response to environmental and functional stimuli within the cell.
- Subjects :
- Ribosomal Proteins
Biology
Biochemistry
Ribosome
Mass Spectrometry
Article
03 medical and health sciences
Ribosomal protein
Escherichia coli
Protein biosynthesis
Peptide Elongation Factor G
Initiation factor
ComputingMilieux_MISCELLANEOUS
030304 developmental biology
0303 health sciences
[SDV.BBM.BS]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Structural Biology [q-bio.BM]
Escherichia coli Proteins
030302 biochemistry & molecular biology
Translation (biology)
General Medicine
Kinetics
Protein Subunits
Biophysics
Molecular Medicine
Protein Multimerization
Eukaryotic Ribosome
Ribosomes
EF-G
Protein Binding
Subjects
Details
- Language :
- English
- ISSN :
- 15548937 and 15548929
- Volume :
- 7
- Issue :
- 6
- Database :
- OpenAIRE
- Journal :
- ACS Chemical Biology
- Accession number :
- edsair.doi.dedup.....5e1e40156648a7f1909077af6fa0d280
- Full Text :
- https://doi.org/10.1021/cb300081s