View source for 6o81


==Electron cryo-microscopy of the eukaryotic translation initiation factor 2B bound to translation initiation factor 2 from Homo sapiens==
<SX load='6o81' size='340' side='right' viewer='molstar' caption='[[6o81]], [[Resolution|resolution]] 3.21&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6o81]] is a 16 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=6O81 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6O81 FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 3.21&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=C7B:2-(4-chloranylphenoxy)-~{N}-[4-[2-(4-chloranylphenoxy)ethanoylamino]cyclohexyl]ethanamide'>C7B</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=6o81 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6o81 OCA], [https://pdbe.org/6o81 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6o81 RCSB], [https://www.ebi.ac.uk/pdbsum/6o81 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6o81 ProSAT]</span></td></tr>
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== Disease ==
[https://www.uniprot.org/uniprot/EI2BE_HUMAN EI2BE_HUMAN] Defects in EIF2B5 are a cause of leukodystrophy with vanishing white matter (VWM) [MIM:[https://omim.org/entry/603896 603896]. VWM is a leukodystrophy that occurs mainly in children. Neurological signs include progressive cerebellar ataxia, spasticity, inconstant optic atrophy and relatively preserved mental abilities. The disease is chronic-progressive with, in most individuals, additional episodes of rapid deterioration following febrile infections or minor head trauma. While childhood onset is the most common form of the disorder, some severe forms are apparent at birth. A severe, early-onset form seen among the Cree and Chippewayan populations of Quebec and Manitoba is called Cree leukoencephalopathy. Milder forms may not become evident until adolescence or adulthood. Some females with milder forms of the disease who survive to adolescence exhibit ovarian dysfunction. This variant of the disorder is called ovarioleukodystrophy.<ref>PMID:11704758</ref> <ref>PMID:12325082</ref> <ref>PMID:12707859</ref> <ref>PMID:15776425</ref> <ref>PMID:19158808</ref> <ref>PMID:21484434</ref> 
== Function ==
[https://www.uniprot.org/uniprot/EI2BE_HUMAN EI2BE_HUMAN] Catalyzes the exchange of eukaryotic initiation factor 2-bound GDP for GTP.
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== Publication Abstract from PubMed ==
The integrated stress response (ISR) tunes the rate of protein synthesis. Control is exerted by phosphorylation of the general translation initiation factor eIF2. eIF2 is a guanosine triphosphatase that becomes activated by eIF2B, a two-fold symmetric and heterodecameric complex that functions as eIF2's dedicated nucleotide exchange factor. Phosphorylation converts eIF2 from a substrate into an inhibitor of eIF2B. We report cryo-electron microscopy structures of eIF2 bound to eIF2B in the dephosphorylated state. The structures reveal that the eIF2B decamer is a static platform upon which one or two flexible eIF2 trimers bind and align with eIF2B's bipartite catalytic centers to catalyze nucleotide exchange. Phosphorylation refolds eIF2alpha, allowing it to contact eIF2B at a different interface and, we surmise, thereby sequestering it into a nonproductive complex.

eIF2B-catalyzed nucleotide exchange and phosphoregulation by the integrated stress response.,Kenner LR, Anand AA, Nguyen HC, Myasnikov AG, Klose CJ, McGeever LA, Tsai JC, Miller-Vedam LE, Walter P, Frost A Science. 2019 May 3;364(6439):491-495. doi: 10.1126/science.aaw2922. PMID:31048491<ref>PMID:31048491</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 6o81" style="background-color:#fffaf0;"></div>

==See Also==
*[[Eukaryotic initiation factor 3D structures|Eukaryotic initiation factor 3D structures]]
== References ==
<references/>
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[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Frost A]]
[[Category: Kenner L]]
[[Category: Nguyen H]]