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Updated: May 12, 2026
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Using SecM Arrest Sequence as a Tool to Isolate Ribosome Bound Polypeptides
Published on: June 19, 2012
A posttermination ribosomal complex is the guanine nucleotide exchange factor for peptide release factor RF3
A V Zavialov1, R H Buckingham, M Ehrenberg
1Department of Cell and Molecular Biology, BMC, Uppsala University, Box 596, S-75124 Uppsala, Sweden. andrey.zavialov@icm.uu.se
Cell
|October 12, 2001
Summary
Peptide release factor RF3 recycles RF1 and RF2 during translation termination. Ribosomes facilitate GTP binding to RF3, promoting RF1/RF2 dissociation, a process common to eukaryotic eRF3.
Area of Science:
- Molecular Biology
- Protein Synthesis
- Biochemistry
Background:
- Translation termination is a critical step in protein synthesis.
- Peptide release factors (RFs) mediate the termination process.
- The recycling mechanism of RF3, RF1, and RF2 was not fully understood.
Purpose of the Study:
- To elucidate the mechanism of peptide release factor RF3 in recycling RF1 and RF2.
- To integrate this mechanism into a comprehensive scheme for translation termination.
- To compare the mechanism of bacterial RF3 with its eukaryotic counterpart, eRF3.
Main Methods:
- In vivo biochemical assays.
- Guanine nucleotide binding and hydrolysis studies.
- Ribosome binding affinity measurements.
Main Results:
- Free RF3 is bound to GDP in vivo.
- Ribosomes complexed with RF1 or RF2 function as guanine nucleotide exchange factors (GEF).
- Peptidyl-tRNA hydrolysis by RF1/RF2 enables GTP binding to RF3, increasing its affinity for ribosomes and causing RF1/RF2 dissociation.
- RF3 dissociation from the ribosome requires GTP hydrolysis.
Conclusions:
- A complete scheme for translation termination involving RF3-mediated recycling of RF1 and RF2 has been established.
- RF3 utilizes a GTP-dependent mechanism for releasing RF1 and RF2 from the ribosome.
- Mechanistic similarities exist between bacterial RF3 and eukaryotic eRF3.
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