View source for 1kl9


==Crystal structure of the N-terminal segment of Human eukaryotic initiation factor 2alpha==
<StructureSection load='1kl9' size='340' side='right'caption='[[1kl9]], [[Resolution|resolution]] 1.90&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1kl9]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1KL9 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1KL9 FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.9&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=MSE:SELENOMETHIONINE'>MSE</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1kl9 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1kl9 OCA], [https://pdbe.org/1kl9 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1kl9 RCSB], [https://www.ebi.ac.uk/pdbsum/1kl9 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1kl9 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/IF2A_HUMAN IF2A_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 ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/kl/1kl9_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1kl9 ConSurf].
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== Publication Abstract from PubMed ==
Eukaryotic 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<ref>PMID:11859078</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 1kl9" style="background-color:#fffaf0;"></div>

==See Also==
*[[Eukaryotic initiation factor 3D structures|Eukaryotic initiation factor 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Clardy J]]
[[Category: Nonato MC]]
[[Category: Widom J]]