3j8b

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== Structural highlights ==
== Structural highlights ==
<table><tr><td colspan='2'>[[3j8b]] is a 8 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. This structure supersedes the now removed PDB entry [http://oca.weizmann.ac.il/oca-bin/send-pdb?obs=1&id=3j7j 3j7j]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3J8B OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3J8B FirstGlance]. <br>
<table><tr><td colspan='2'>[[3j8b]] is a 8 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. This structure supersedes the now removed PDB entry [http://oca.weizmann.ac.il/oca-bin/send-pdb?obs=1&id=3j7j 3j7j]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3J8B OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3J8B FirstGlance]. <br>
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</td></tr><tr id='NonStdRes'><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><scene name='pdbligand=UNK:UNKNOWN'>UNK</scene></td></tr>
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</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 9.3&#8491;</td></tr>
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<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat"><div style='overflow: auto; max-height: 3em;'>[[3j8c|3j8c]], [[4u1d|4u1d]], [[4u1c|4u1c]], [[4lct|4lct]], [[4b4t|4b4t]], [[4o8x|4o8x]], [[1rz4|1rz4]], [[3chm|3chm]], [[3j47|3j47]]</div></td></tr>
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<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/Ubiquitinyl_hydrolase_1 Ubiquitinyl hydrolase 1], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.19.12 3.4.19.12] </span></td></tr>
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<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=3j8b FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3j8b OCA], [https://pdbe.org/3j8b PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3j8b RCSB], [https://www.ebi.ac.uk/pdbsum/3j8b PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3j8b ProSAT]</span></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=3j8b FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3j8b OCA], [https://pdbe.org/3j8b PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3j8b RCSB], [https://www.ebi.ac.uk/pdbsum/3j8b PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3j8b ProSAT]</span></td></tr>
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</table>
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<div style="background-color:#fffaf0;">
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== Function ==
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== Publication Abstract from PubMed ==
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[https://www.uniprot.org/uniprot/EIF3A_HUMAN EIF3A_HUMAN] RNA-binding component of the eukaryotic translation initiation factor 3 (eIF-3) complex, which is required for several steps in the initiation of protein synthesis (PubMed:17581632, PubMed:25849773). The eIF-3 complex associates with the 40S ribosome and facilitates the recruitment of eIF-1, eIF-1A, eIF-2:GTP:methionyl-tRNAi and eIF-5 to form the 43S pre-initiation complex (43S PIC). The eIF-3 complex stimulates mRNA recruitment to the 43S PIC and scanning of the mRNA for AUG recognition. The eIF-3 complex is also required for disassembly and recycling of post-termination ribosomal complexes and subsequently prevents premature joining of the 40S and 60S ribosomal subunits prior to initiation (PubMed:17581632, PubMed:11169732). The eIF-3 complex specifically targets and initiates translation of a subset of mRNAs involved in cell proliferation, including cell cycling, differentiation and apoptosis, and uses different modes of RNA stem-loop binding to exert either translational activation or repression (PubMed:25849773, PubMed:27462815).[HAMAP-Rule:MF_03000]<ref>PMID:11169732</ref> <ref>PMID:17581632</ref> <ref>PMID:25849773</ref> <ref>PMID:27462815</ref> (Microbial infection) Essential for the initiation of translation on type-1 viral ribosomal entry sites (IRESs), like for HCV, PV, EV71 or BEV translation (PubMed:23766293, PubMed:24357634).<ref>PMID:23766293</ref> <ref>PMID:24357634</ref> (Microbial infection) In case of FCV infection, plays a role in the ribosomal termination-reinitiation event leading to the translation of VP2 (PubMed:18056426).<ref>PMID:18056426</ref>
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Hepatitis C virus (HCV) and classical swine fever virus (CSFV) messenger RNAs contain related (HCV-like) internal ribosome entry sites (IRESs) that promote 5'-end independent initiation of translation, requiring only a subset of the eukaryotic initiation factors (eIFs) needed for canonical initiation on cellular mRNAs. Initiation on HCV-like IRESs relies on their specific interaction with the 40S subunit, which places the initiation codon into the P site, where it directly base-pairs with eIF2-bound initiator methionyl transfer RNA to form a 48S initiation complex. However, all HCV-like IRESs also specifically interact with eIF3 (refs 2, 5, 6, 7, 9, 10, 11, 12), but the role of this interaction in IRES-mediated initiation has remained unknown. During canonical initiation, eIF3 binds to the 40S subunit as a component of the 43S pre-initiation complex, and comparison of the ribosomal positions of eIF3 and the HCV IRES revealed that they overlap, so that their rearrangement would be required for formation of ribosomal complexes containing both components. Here we present a cryo-electron microscopy reconstruction of a 40S ribosomal complex containing eIF3 and the CSFV IRES. Remarkably, although the position and interactions of the CSFV IRES with the 40S subunit in this complex are similar to those of the HCV IRES in the 40S-IRES binary complex, eIF3 is completely displaced from its ribosomal position in the 43S complex, and instead interacts through its ribosome-binding surface exclusively with the apical region of domain III of the IRES. Our results suggest a role for the specific interaction of HCV-like IRESs with eIF3 in preventing ribosomal association of eIF3, which could serve two purposes: relieving the competition between the IRES and eIF3 for a common binding site on the 40S subunit, and reducing formation of 43S complexes, thereby favouring translation of viral mRNAs.
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Hepatitis-C-virus-like internal ribosome entry sites displace eIF3 to gain access to the 40S subunit.,Hashem Y, des Georges A, Dhote V, Langlois R, Liao HY, Grassucci RA, Pestova TV, Hellen CU, Frank J Nature. 2013 Nov 3. doi: 10.1038/nature12658. PMID:24185006<ref>PMID:24185006</ref>
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From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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</div>
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<div class="pdbe-citations 3j8b" style="background-color:#fffaf0;"></div>
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==See Also==
==See Also==
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[[Category: Homo sapiens]]
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Large Structures]]
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[[Category: Ubiquitinyl hydrolase 1]]
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[[Category: Ban N]]
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[[Category: Ban, N]]
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[[Category: Erzberger JP]]
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[[Category: Erzberger, J P]]
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[[Category: Translation]]
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Current revision

Model of the human eIF3 PCI-MPN octamer docked into the 43S-HCV IRES EM map

3j8b, resolution 9.30Å

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OCA

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