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Initiation factor eIF5B catalyzes second GTP-dependent step in eukaryotic translation initiation.

Joon H Lee·Tatyana V Pestova·Byung-Sik Shin·Chune Cao·Sang K Choi·Thomas E Dever
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Abstract

Initiation factors IF2 in bacteria and eIF2 in eukaryotes are GTPases that bind Met-tRNA(i)(Met) to the small ribosomal subunit. eIF5B, the eukaryotic ortholog of IF2, is a GTPase that promotes ribosomal subunit joining. Here we show that eIF5B GTPase activity is required for protein synthesis. Mutation of the conserved Asp-759 in human eIF5B GTP-binding domain to Asn converts eIF5B to an XTPase and introduces an XTP requirement for subunit joining and translation initiation. Thus, in contrast to bacteria where the single GTPase IF2 is sufficient to catalyze translation initiation, eukaryotic cells require hydrolysis of GTP by both eIF2 and eIF5B to complete translation initiation.

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CatalysisCell DivisionCodonConserved SequenceDNA-Binding ProteinsEukaryotic Initiation FactorsGuanosine TriphosphateMutationOpen Reading FramesProtein BiosynthesisProtein KinasesSaccharomyces cerevisiae ProteinsJournal ArticleResearch Support, U.S. Gov't, P.H.S.

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Joon H Lee, Tatyana V Pestova, Byung-Sik Shin, Chune Cao, Sang K Choi, Thomas E Dever. 2002-12-06. Initiation factor eIF5B catalyzes second GTP-dependent step in eukaryotic translation initiation.. https://doi.org/10.1073/pnas.262569399

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