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Distinct roles for release factor 1 and release factor 2 in translational quality control
Alexandros D Petropoulos1, Megan E McDonald1, Rachel Green1
1From the Howard Hughes Medical Institute, Department of Molecular Biology and Genetics, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205 and.
The Journal of Biological Chemistry
|May 7, 2014
Summary
Bacterial release factor 2 (RF2) plays a key role in quality control by recognizing mismatched ribosome complexes. RF2, with release factor 3 (RF3), ensures accurate protein synthesis termination.
Area of Science:
- Molecular Biology
- Bacterial Protein Synthesis
- Genetics
Background:
- Bacteria utilize class 1 release factors (RF1, RF2) to recognize stop codons.
- Class 2 release factor 3 (RF3) facilitates ribosome recycling after termination.
- Release factors are also involved in a post-peptidyl transfer quality control (post PT QC) mechanism.
Purpose of the Study:
- To investigate the roles of RF1, RF2, and RF3 in canonical termination and post PT QC.
- To elucidate the specific functions of release factors in error-containing ribosome complexes.
Main Methods:
- Utilized a well-defined in vitro system to study release factor functions.
- Analyzed the binding and dissociation kinetics of RF1, RF2, and RF3 on canonical and mismatched ribosome complexes.
Main Results:
- RF1 and RF2 recognize stop codons similarly during canonical termination, with RF3 accelerating dissociation.
- During post PT QC, only RF2 effectively binds mismatched complexes.
- RF3 enhances RF2's release rate on mismatched complexes but inhibits RF1's release while increasing peptidyl-tRNA dissociation.
Conclusions:
- RF2 is the primary factor for post PT QC, in addition to its role in peptide release.
- The distinct roles of RF1 and RF2 in post PT QC highlight a nuanced quality control mechanism in bacteria.
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