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Crystal structure of the N-terminal segment of Human eukaryotic initiation factor 2alphaCrystal structure of the N-terminal segment of Human eukaryotic initiation factor 2alpha
Structural highlights
FunctionIF2A_HUMAN Functions in the early steps of protein synthesis by forming a ternary complex with GTP and initiator tRNA. This complex binds to a 40S ribosomal subunit, followed by mRNA binding to form a 43S preinitiation complex. Junction of the 60S ribosomal subunit to form the 80S initiation complex is preceded by hydrolysis of the GTP bound to eIF-2 and release of an eIF-2-GDP binary complex. In order for eIF-2 to recycle and catalyze another round of initiation, the GDP bound to eIF-2 must exchange with GTP by way of a reaction catalyzed by eIF-2B. 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 PubMedEukaryotic translation initiation factor 2alpha (eIF2alpha) is a member of the eIF2 heterotrimeric complex that binds and delivers Met-tRNA(i)(Met) to the 40 S ribosomal subunit in a GTP-dependent manner. Phosphorylation/dephosphorylation of eIF2alpha at Ser-51 is the major regulator of protein synthesis in eukaryotic cells. Here, we report the first structural analysis on eIF2, the three-dimensional structure of a 22-kDa N-terminal portion of human eIF2alpha by x-ray diffraction at 1.9 A resolution. This structure contains two major domains. The N terminus is a beta-barrel with five antiparallel beta-strands in an oligonucleotide binding domain (OB domain) fold. The phosphorylation site (Ser-51) is on the loop connecting beta3 and beta4 in the OB domain. A helical domain follows the OB domain, and the first helix has extensive interactions, including a disulfide bridge, to fix its orientation with respect to the OB domain. The two domains meet along a negatively charged groove with highly conserved residues, indicating a likely site for protein-protein interaction. Crystal structure of the N-terminal segment of human eukaryotic translation initiation factor 2alpha.,Nonato MC, Widom J, Clardy J J Biol Chem. 2002 May 10;277(19):17057-61. Epub 2002 Feb 21. PMID:11859078[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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