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==== | ==Structure of the wt IRES and 40S ribosome binary complex, open conformation. Structure 10(wt)== | ||
<StructureSection load='7syp' size='340' side='right'caption='[[7syp]]' scene=''> | <StructureSection load='7syp' size='340' side='right'caption='[[7syp]], [[Resolution|resolution]] 4.00Å' scene=''> | ||
== Structural highlights == | == Structural highlights == | ||
<table><tr><td colspan='2'>Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id= OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol= FirstGlance]. <br> | <table><tr><td colspan='2'>[[7syp]] is a 10 chain structure with sequence from [https://en.wikipedia.org/wiki/Oryctolagus_cuniculus Oryctolagus cuniculus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7SYP OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7SYP FirstGlance]. <br> | ||
</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=7syp FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7syp OCA], [https://pdbe.org/7syp PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7syp RCSB], [https://www.ebi.ac.uk/pdbsum/7syp PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7syp ProSAT]</span></td></tr> | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 4Å</td></tr> | ||
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><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=7syp FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7syp OCA], [https://pdbe.org/7syp PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7syp RCSB], [https://www.ebi.ac.uk/pdbsum/7syp PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7syp ProSAT]</span></td></tr> | |||
</table> | </table> | ||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
Hepatitis C virus mRNA contains an internal ribosome entry site (IRES) that mediates end-independent translation initiation, requiring a subset of eukaryotic initiation factors (eIFs). Biochemical studies revealed that direct binding of the IRES to the 40S ribosomal subunit places the initiation codon into the P site, where it base pairs with eIF2-bound Met-tRNAiMet forming a 48S initiation complex. Subsequently, eIF5 and eIF5B mediate subunit joining, yielding an elongation-competent 80S ribosome. Initiation can also proceed without eIF2, in which case Met-tRNAiMet is recruited directly by eIF5B. However, the structures of initiation complexes assembled on the HCV IRES, the transitions between different states, and the accompanying conformational changes have remained unknown. To fill these gaps, we now obtained cryo-EM structures of IRES initiation complexes, at resolutions up to 3.5 A, that cover all major stages from the initial ribosomal association, through eIF2-containing 48S initiation complexes, to eIF5B-containing complexes immediately prior to subunit joining. These structures provide insights into the dynamic network of 40S/IRES contacts, highlight the role of IRES domain II, and reveal conformational changes that occur during the transition from eIF2- to eIF5B-containing 48S complexes and prepare them for subunit joining. | |||
Molecular architecture of 40S translation initiation complexes on the hepatitis C virus IRES.,Brown ZP, Abaeva IS, De S, Hellen CUT, Pestova TV, Frank J EMBO J. 2022 Aug 16;41(16):e110581. doi: 10.15252/embj.2022110581. Epub 2022 Jul , 13. PMID:35822879<ref>PMID:35822879</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 7syp" style="background-color:#fffaf0;"></div> | |||
==See Also== | |||
*[[Ribosome 3D structures|Ribosome 3D structures]] | |||
== References == | |||
<references/> | |||
__TOC__ | __TOC__ | ||
</StructureSection> | </StructureSection> | ||
[[Category: Large Structures]] | [[Category: Large Structures]] | ||
[[Category: | [[Category: Oryctolagus cuniculus]] | ||
[[Category: Abaeva IS]] | |||
[[Category: Brown ZP]] | |||
[[Category: De S]] | |||
[[Category: Frank J]] | |||
[[Category: Hellen CUT]] | |||
[[Category: Pestova TV]] | |||
Latest revision as of 12:11, 17 October 2024
Structure of the wt IRES and 40S ribosome binary complex, open conformation. Structure 10(wt)Structure of the wt IRES and 40S ribosome binary complex, open conformation. Structure 10(wt)
Structural highlights
Publication Abstract from PubMedHepatitis C virus mRNA contains an internal ribosome entry site (IRES) that mediates end-independent translation initiation, requiring a subset of eukaryotic initiation factors (eIFs). Biochemical studies revealed that direct binding of the IRES to the 40S ribosomal subunit places the initiation codon into the P site, where it base pairs with eIF2-bound Met-tRNAiMet forming a 48S initiation complex. Subsequently, eIF5 and eIF5B mediate subunit joining, yielding an elongation-competent 80S ribosome. Initiation can also proceed without eIF2, in which case Met-tRNAiMet is recruited directly by eIF5B. However, the structures of initiation complexes assembled on the HCV IRES, the transitions between different states, and the accompanying conformational changes have remained unknown. To fill these gaps, we now obtained cryo-EM structures of IRES initiation complexes, at resolutions up to 3.5 A, that cover all major stages from the initial ribosomal association, through eIF2-containing 48S initiation complexes, to eIF5B-containing complexes immediately prior to subunit joining. These structures provide insights into the dynamic network of 40S/IRES contacts, highlight the role of IRES domain II, and reveal conformational changes that occur during the transition from eIF2- to eIF5B-containing 48S complexes and prepare them for subunit joining. Molecular architecture of 40S translation initiation complexes on the hepatitis C virus IRES.,Brown ZP, Abaeva IS, De S, Hellen CUT, Pestova TV, Frank J EMBO J. 2022 Aug 16;41(16):e110581. doi: 10.15252/embj.2022110581. Epub 2022 Jul , 13. PMID:35822879[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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