WordNet

a unit of force equal to the force exerted by gravity; used to indicate the force to which a body is subjected when it is accelerated (同)gee, g-force
the 7th letter of the Roman alphabet (同)g
the 5th letter of the Roman alphabet (同)e

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/01/22 23:09:49」(JST)

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EF-G or elongation factor G (historically known as translocase) is one of the prokaryotic elongation factors.

Function[edit]

The factor EF-G catalyzes the translocation of the tRNA and mRNA down the ribosome at the end of each round of polypeptide elongation. Homologous to EF-Tu + tRNA, EF-G also binds to the ribosome in its GTP-bound state. When it associates with the A site, EF-G causes the tRNA previously occupying that site to occupy an intermediate A/P position (bound to the A site of the small ribosomal subunit and to the P site of the large subunit), and the tRNA in the P site is shifted to a P/E hybrid state. EF-G hydrolysis of GTP causes a conformation change that forces the A/P tRNA to fully occupy the P site, the P/E tRNA to fully occupy the E site (and exit the ribosome complex), and the mRNA to shift three nucleotides down relative to the ribosome due to its association with these tRNA molecules. The GDP-bound EF-G molecule then dissociates from the complex, leaving another free A-site where the elongation cycle can start again.

Apart from its role in translocation, EF-G, working together with Ribosome Recycling Factor promotes ribosome recycling in a GTP-dependent manner.^[1]

Clinical significance[edit]

It is normally inhibited by fusidic acid, but resistance has emerged.^[2]^[3]

Evolution[edit]

EF-G has a complex evolutionary history, with numerous paralogous versions of the factor present in bacteria, suggesting subfunctionalization of different EF-G variants.^[4]

References[edit]

^ Zavialov AV, Hauryliuk VV, Ehrenberg M. (2005). "Splitting of the posttermination ribosome into subunits by the concerted action of RRF and EF-G". Molecular Cell 18 (6): 675–686. doi:10.1016/j.molcel.2005.05.016. PMID 15949442.
^ Macvanin M, Hughes D (June 2005). "Hyper-susceptibility of a fusidic acid-resistant mutant of Salmonella to different classes of antibiotics". FEMS microbiology letters 247 (2): 215–20. doi:10.1016/j.femsle.2005.05.007. PMID 15935566.
^ Macvanin M, Johanson U, Ehrenberg M, Hughes D (July 2000). "Fusidic acid-resistant EF-G perturbs the accumulation of ppGpp". Molecular microbiology 37 (1): 98–107. doi:10.1046/j.1365-2958.2000.01967.x. PMID 10931308.
^ G C Atkinson, S L Baldauf (2011). "Evolution of elongation factor G and the origins of mitochondrial and chloroplast forms". Molecular Biology and Evolution 28 (3): 1281–92. doi:10.1093/molbev/msq316. PMID 21097998.

External links[edit]

Peptide Elongation Factor G at the US National Library of Medicine Medical Subject Headings (MeSH)

UpToDate Contents

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English Journal

Efficient Assembly of Ribosomes Is Inhibited by Deletion of bipA in Escherichia coli.

Choudhury P1, Flower AM2.
Journal of bacteriology.J Bacteriol.2015 May 15;197(10):1819-27. doi: 10.1128/JB.00023-15. Epub 2015 Mar 16.
The bacterial BipA protein belongs to the EF-G family of translational GTPases and has been postulated to be either a regulatory translation factor or a ribosome assembly factor. To distinguish between these hypotheses, we analyzed the effect of bipA deletion on three phenotypes associated with ribo
PMID 25777676

Role of a ribosomal RNA phosphate oxygen during the EF-G-triggered GTP hydrolysis.

Koch M1, Flür S2, Kreutz C2, Ennifar E3, Micura R4, Polacek N5.
Proceedings of the National Academy of Sciences of the United States of America.Proc Natl Acad Sci U S A.2015 May 4. pii: 201505231. [Epub ahead of print]
Elongation factor-catalyzed GTP hydrolysis is a key reaction during the ribosomal elongation cycle. Recent crystal structures of G proteins, such as elongation factor G (EF-G) bound to the ribosome, as well as many biochemical studies, provide evidence that the direct interaction of translational GT
PMID 25941362