1vb5
From Proteopedia
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Crystal Structure Analysis of the Pyrococcus horikoshii OT3 translation initiation factor eIF-2B
Overview
Eukaryotic translation initiation factor 2B (eIF2B) is the, guanine-nucleotide exchange factor for eukaryotic initiation factor 2, (eIF2). eIF2B is a heteropentameric protein composed of alpha- subunits., The alpha, beta, and delta subunits form a regulatory subcomplex, while, the gamma and form a catalytic subcomplex. Archaea possess homologues of, alpha, beta, and delta subunits of eIF2B. Here, we report the, three-dimensional structure of an archaeal regulatory subunit (aIF2Balpha), from the hyperthermophilic archaeon Pyrococcus horikoshii OT3 determined, by X-ray crystallography at 2.2A resolution. aIF2Balpha consists of two, subdomains, an N-domain (residues 1-95) and a C-domain (residues 96-276), connected by a long alpha-helix (alpha5: 78-106). The N-domain contains a, five helix bundle structure, while the C-domain folds into the alpha/beta, structure, thus showing similarity to D-ribose-5-phosphate isomerase, structure. The presence of two molecules in the crystallographic, asymmetric unit and the gel filtration analysis suggest a dimeric, structure of aIF2Balpha in solution, interacting with each other by, C-domains. Furthermore, the crystallographic 3-fold symmetry generates a, homohexameric structure of aIF2Balpha; the interaction is primarily, mediated by the long alpha-helix at the N-domains. This structure suggests, an architecture of the three subunits, alpha, beta, and delta, in the, regulatory subcomplex within eIF2B.
About this Structure
1VB5 is a Single protein structure of sequence from Pyrococcus horikoshii. Full crystallographic information is available from OCA.
Reference
Crystal structure of the regulatory subunit of archaeal initiation factor 2B (aIF2B) from hyperthermophilic archaeon Pyrococcus horikoshii OT3: a proposed structure of the regulatory subcomplex of eukaryotic IF2B., Kakuta Y, Tahara M, Maetani S, Yao M, Tanaka I, Kimura M, Biochem Biophys Res Commun. 2004 Jul 2;319(3):725-32. PMID:15184043
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