Biology:Ribosome recycling factor
| Ribosome recycling factor | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||
| Symbol | RRF | ||||||||
| Pfam | PF01765 | ||||||||
| InterPro | IPR002661 | ||||||||
| CATH | 1ek8 | ||||||||
| SCOP2 | 1ek8 / SCOPe / SUPFAM | ||||||||
| CDD | cd00520 | ||||||||
| |||||||||
 Generic protein structure example |
Ribosome recycling factor or ribosome release factor (RRF) is a protein found in bacterial cells as well as eukaryotic organelles, specifically mitochondria and chloroplasts. It functions to recycle ribosomes after completion of protein synthesis (bacterial translation). In humans, the mitochrondrial version is coded by the MRRF gene.
Structure
The mitochondrial ribosome-recycling factor is a soluble member of the conserved ribosome-recycling factor (RRF) family. The mature mitochondrial form retains the characteristic two-domain, L-shaped/tRNA-mimetic architecture of bacterial RRFs. Its conserved core consists of two domains joined by a flexible hinge. The first an elongated, mainly α-helical domain I that forms one arm of the L, and the second, a smaller domain with a mixed α/β fold that forms the other arm. The hinge allows the two domains to move relative to one another during ribosome recycling. In mitochondria, this conserved core is preceded by an additional N-terminal extension that contributes mitochondria-specific interactions with the mitoribosome.[1][2]
The crystal structure of RRF was first determined by X-ray diffraction in 1999.[3] The most striking revelation was that RRF is a near-perfect structural mimic of tRNA, in both size and dimensions.
Despite the tRNA-mimicry, RRF binds to ribosomes quite differently from the way tRNA does.[4] It has been suggested that ribosomes bind proteins (or protein domain) of similar shape and size to tRNA, and this, rather than function, explains the observed structural mimicry.
Function
RRF accomplishes the recycling of ribosomes by splitting ribosomes into subunits, thereby releasing the bound mRNA. This also requires the participation of EF-G (GFM2 in humans).[5] Depending on the tRNA, IF1–IF3 may also perform recycling.[6]
Loss of RRF function
- In Bacteria (specifically Escherichia coli), loss of the gene encoding RRF is deleterious.[7] This makes RRF a possible target for new antibacterial drugs.
- Yeast mitochondrial RRF (mtRRF) is encoded by a gene in the cell nucleus. Loss of function of this gene leads to mitochondrial genome instability and respiratory incompetence.[8]
Discovery
The ribosome recycling factor was discovered in the early 1970s by the work of Akira Kaji and Akikazu Hiroshima at the University of Pennsylvania.[9][10][11][12] Their work described the requirement for two protein factors to release ribosomes from mRNA. These two factors were identified as RRF, an unknown protein until then, and Elongation Factor G (EF-G), a protein already identified and known to function in protein synthesis. RRF was originally called Ribosome Releasing Factor but is now called Ribosome Recycling Factor.
See also
- Ribosome
- Translation (genetics)
- Eukaryotic release factors
References
- ↑ "Structural insights into unique features of the human mitochondrial ribosome recycling". Proceedings of the National Academy of Sciences of the United States of America 116 (17): 8283–8288. April 2019. doi:10.1073/pnas.1815675116. PMID 30962385.
- ↑ "Structural basis of translation termination, rescue, and recycling in mammalian mitochondria". Molecular cell 81 (12): 2566–2582.e6. June 2021. doi:10.1016/j.molcel.2021.03.042. PMID 33878294.
- ↑ "Crystal structure of Thermotoga maritima ribosome recycling factor: a tRNA mimic". Science (New York, N.Y.) 286 (5448): 2349–2352. December 1999. doi:10.1126/science.286.5448.2349. PMID 10600747.
- ↑ "Visualization of ribosome-recycling factor on the Escherichia coli 70S ribosome: functional implications". Proceedings of the National Academy of Sciences of the United States of America 101 (24): 8900–8905. June 2004. doi:10.1073/pnas.0401904101. PMID 15178758. Bibcode: 2004PNAS..101.8900A.
- ↑ "The ribosome-recycling step: Consensus or controversy?". Trends in Biochemical Sciences 31 (3): 143–149. March 2006. doi:10.1016/j.tibs.2006.01.007. PMID 16487710. https://jdc.jefferson.edu/cgi/viewcontent.cgi?article=1005&context=bmpfp.
- ↑ "Complementary roles of initiation factor 1 and ribosome recycling factor in 70S ribosome splitting". The EMBO Journal 27 (12): 1706–1717. June 2008. doi:10.1038/emboj.2008.99. PMID 18497739.
- ↑ "Ribosome recycling factor (ribosome releasing factor) is essential for bacterial growth". Proceedings of the National Academy of Sciences of the United States of America 91 (10): 4249–4253. May 1994. doi:10.1073/pnas.91.10.4249. PMID 8183897. Bibcode: 1994PNAS...91.4249J.
- ↑ "Temperature-sensitive mutation in yeast mitochondrial ribosome recycling factor (RRF)". Nucleic Acids Research 31 (14): 4218–4226. July 2003. doi:10.1093/nar/gkg449. PMID 12853640.
- ↑ "Factor dependent breakdown of polysomes". Biochemical and Biophysical Research Communications 41 (4): 877–883. November 1970. doi:10.1016/0006-291X(70)90165-8. PMID 4920474. Bibcode: 1970BBRC...41..877H.
- ↑ "Factor-dependent release of ribosomes from messenger RNA. Requirement for two heat-stable factors". Journal of Molecular Biology 65 (1): 43–58. March 1972. doi:10.1016/0022-2836(72)90490-1. PMID 4553259.
- ↑ "Purification and properties of ribosome-releasing factor". Biochemistry 11 (22): 4037–4044. October 1972. doi:10.1021/bi00772a005. PMID 4563926.
- ↑ "Role of elongation factor G and a protein factor on the release of ribosomes from messenger ribonucleic acid". The Journal of Biological Chemistry 248 (21): 7580–7587. November 1973. doi:10.1016/S0021-9258(19)43330-9. PMID 4583357.
External links
- ribosome+releasing+factor at the US National Library of Medicine Medical Subject Headings (MeSH)
- "Rate-limiting hydrolysis in ribosomal release reactions revealed by ester activation". The Journal of Biological Chemistry 298 (11). November 2022. doi:10.1016/j.jbc.2022.102509. PMID 36300356.
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