EF-G is one of the prokaryotic elongation factors.
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Function
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.
EF-G is also involved with Ribosome Recycling Factor in ribosome recycling.
Clinical significance
It is normally inhibited by fusidic acid, but resistance has emerged.[1][2]
References
- ^ 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:. PMID 15935566. http://linkinghub.elsevier.com/retrieve/pii/S0378-1097(05)00289-2.
- ^ 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. PMID 10931308. http://www.blackwell-synergy.com/openurl?genre=article&sid=nlm:pubmed&issn=0950-382X&date=2000&volume=37&issue=1&spage=98.
External links
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