View source for 6ybv


==Structure of a human 48S translational initiation complex - eIF2-TC==
<StructureSection load='6ybv' size='340' side='right'caption='[[6ybv]], [[Resolution|resolution]] 3.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6ybv]] is a 5 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=6YBV OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6YBV 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]] 3.8&#8491;</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=6ybv FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6ybv OCA], [https://pdbe.org/6ybv PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6ybv RCSB], [https://www.ebi.ac.uk/pdbsum/6ybv PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6ybv ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/IF2B_HUMAN IF2B_HUMAN] eIF-2 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.
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
A key step in translational initiation is the recruitment of the 43S preinitiation complex by the cap-binding complex [eukaryotic initiation factor 4F (eIF4F)] at the 5' end of messenger RNA (mRNA) to form the 48S initiation complex (i.e., the 48S). The 48S then scans along the mRNA to locate a start codon. To understand the mechanisms involved, we used cryo-electron microscopy to determine the structure of a reconstituted human 48S The structure reveals insights into early events of translation initiation complex assembly, as well as how eIF4F interacts with subunits of eIF3 near the mRNA exit channel in the 43S The location of eIF4F is consistent with a slotting model of mRNA recruitment and suggests that downstream mRNA is unwound at least in part by being "pulled" through the 40S subunit during scanning.

Structure of a human 48S translational initiation complex.,Brito Querido J, Sokabe M, Kraatz S, Gordiyenko Y, Skehel JM, Fraser CS, Ramakrishnan V Science. 2020 Sep 4;369(6508):1220-1227. doi: 10.1126/science.aba4904. PMID:32883864<ref>PMID:32883864</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 6ybv" 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: Brito Querido J]]
[[Category: Fraser C]]
[[Category: Gordiyenko Y]]
[[Category: Kraatz S]]
[[Category: Ramakrishnan V]]
[[Category: Skehel M]]
[[Category: Sokabe M]]