Crystal structure of translation initiation factor aIF2betagamma heterodimer with GDPCrystal structure of translation initiation factor aIF2betagamma heterodimer with GDP

Structural highlights

2dcu is a 2 chain structure with sequence from Pyrococcus furiosus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Ligands:, ,
Related:2d74
Gene:PF1717 (Pyrococcus furiosus), PF0481 (Pyrococcus furiosus)
Resources:FirstGlance, OCA, RCSB, PDBsum

Evolutionary Conservation

 

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

Archaeal/eukaryotic initiation factor 2 (a/eIF2) consists of alpha-, beta-, and gamma-subunits and delivers initiator methionine tRNA (Met-tRNA(i)) to a small ribosomal subunit in a GTP-dependent manner. The structures of the aIF2betagamma (archaeal initiation factor 2 betagamma) heterodimeric complex in the apo and GDP forms were analyzed at 2.8- and 3.4-A resolution, respectively. The results showed that the N-terminal helix and the central helix-turn-helix domain of the beta-subunit bind to the G domain of the gamma-subunit but are distant from domains 2 and 3, to which the alpha-subunit and Met-tRNA(i) bind. This result is consistent with most of the previous analyses of eukaryotic factors, and thus indicates that the binding mode is essentially conserved among a/eIF2. Comparison with the uncomplexed structure showed significant differences between the two forms of the beta-subunit, particularly the C-terminal zinc-binding domain, which does not interact with the gamma-subunit and was suggested previously to be involved in GTP hydrolysis. Furthermore, the switch 1 region in the gamma-subunit, which is shown to be responsible for Met-tRNA(i) binding by mutational analysis, is moved away from the nucleotide through the interaction with highly conserved R87 in the beta-subunit. These results implicate that conformational change of the beta-subunit facilitates GTP hydrolysis by inducing the conformational change of the switch 1 region toward the off state.

Structure of archaeal translational initiation factor 2 betagamma-GDP reveals significant conformational change of the beta-subunit and switch 1 region.,Sokabe M, Yao M, Sakai N, Toya S, Tanaka I Proc Natl Acad Sci U S A. 2006 Aug 29;103(35):13016-21. Epub 2006 Aug 21. PMID:16924118[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

  1. Sokabe M, Yao M, Sakai N, Toya S, Tanaka I. Structure of archaeal translational initiation factor 2 betagamma-GDP reveals significant conformational change of the beta-subunit and switch 1 region. Proc Natl Acad Sci U S A. 2006 Aug 29;103(35):13016-21. Epub 2006 Aug 21. PMID:16924118

2dcu, resolution 3.40Å

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