1VB5

Crystal Structure Analysis of the Pyrococcus horikoshii OT3 translation initiation factor eIF-2B

Summary for 1VB5

• Entry DOI: 10.2210/pdb1vb5/pdb
• Descriptor: translation initiation factor eIF-2B (2 entities in total)
• Functional Keywords: initiation factor, translation
• Biological source: Pyrococcus horikoshii
• Total number of polymer chains: 2
• Total formula weight: 62889.14

Authors

Kakuta, Y.,Tahara, M.,Maetani, S.,Kimura, M. (deposition date: 2004-02-22, release date: 2004-12-07, Last modification date: 2023-12-27)

Primary citation

Kakuta, Y.,Tahara, M.,Maetani, S.,Yao, M.,Tanaka, I.,Kimura, M.
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
Biochem.Biophys.Res.Commun., 319:725-732, 2004

PubMed Abstract: 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.

PubMed: 15184043
DOI: 10.1016/j.bbrc.2004.05.045

Experimental method

X-RAY DIFFRACTION (2.2 Å)