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Elongation factor G (EF-G) family Translocation is mediated by EF-G (also called translocase). The structure of EF-G closely resembles that of the complex between EF-Tu and tRNA. This is an example of molecular mimicry; a protein domain evolved so that it mimics the shape of a tRNA molecule. EF-G in the GTP form binds to the ribosome, primarily through the interaction of its EF-Tu-like domain with the 50S subunit. The binding of EF-G to the ribosome in this manner stimulates the GTPase activity of EF-G. On GTP hydrolysis, EF-G undergoes a conformational change that forces its arm deeper into the A site on the 30S subunit. To accommodate this domain, the peptidyl-tRNA in the A site moves to the P site, carrying the mRNA and the deacylated tRNA with it. The ribosome may be prepared for these rearrangements by the initial binding of EF-G as well. The dissociation of EF-G leaves the ribosome ready to accept the next aminoacyl-tRNA into the A site. This group contains only bacterial members.
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Jiyao W et al.(2023). "The conserved domain database in 2023.",