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Yorodumi- PDB-9kn5: Structure of the human 40S ribosome complexed with HCV IRES, eIF1... -
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Basic information
| Entry | Database: PDB / ID: 9kn5 | ||||||||||||||||||||||||
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| Title | Structure of the human 40S ribosome complexed with HCV IRES, eIF1A and eIF3 | ||||||||||||||||||||||||
Components |
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Keywords | RIBOSOME / HCV IRES | ||||||||||||||||||||||||
| Function / homology | Function and homology informationviral translational termination-reinitiation / eukaryotic translation initiation factor 3 complex, eIF3e / cap-dependent translational initiation / eukaryotic translation initiation factor 3 complex, eIF3m / IRES-dependent viral translational initiation / translation reinitiation / formation of cytoplasmic translation initiation complex / multi-eIF complex / eukaryotic translation initiation factor 3 complex / eukaryotic 43S preinitiation complex ...viral translational termination-reinitiation / eukaryotic translation initiation factor 3 complex, eIF3e / cap-dependent translational initiation / eukaryotic translation initiation factor 3 complex, eIF3m / IRES-dependent viral translational initiation / translation reinitiation / formation of cytoplasmic translation initiation complex / multi-eIF complex / eukaryotic translation initiation factor 3 complex / eukaryotic 43S preinitiation complex / translation factor activity, RNA binding / mRNA cap binding / eukaryotic 48S preinitiation complex / negative regulation of endoplasmic reticulum unfolded protein response / oxidized pyrimidine DNA binding / response to TNF agonist / positive regulation of base-excision repair / positive regulation of ubiquitin-protein transferase activity / regulation of translational initiation / positive regulation of respiratory burst involved in inflammatory response / positive regulation of gastrulation / protein tyrosine kinase inhibitor activity / positive regulation of DNA-templated transcription initiation / positive regulation of intrinsic apoptotic signaling pathway in response to DNA damage / IRE1-RACK1-PP2A complex / positive regulation of Golgi to plasma membrane protein transport / nuclear-transcribed mRNA catabolic process, nonsense-mediated decay / nucleolus organization / TNFR1-mediated ceramide production / negative regulation of RNA splicing / neural crest cell differentiation / metal-dependent deubiquitinase activity / supercoiled DNA binding / cytoplasmic translational initiation / NF-kappaB complex / negative regulation of DNA repair / oxidized purine DNA binding / cysteine-type endopeptidase activator activity involved in apoptotic process / rRNA modification in the nucleus and cytosol / negative regulation of intrinsic apoptotic signaling pathway in response to hydrogen peroxide / negative regulation of bicellular tight junction assembly / ubiquitin-like protein conjugating enzyme binding / regulation of establishment of cell polarity / negative regulation of phagocytosis / erythrocyte homeostasis / cytoplasmic side of rough endoplasmic reticulum membrane / Formation of the ternary complex, and subsequently, the 43S complex / ion channel inhibitor activity / protein kinase A binding / laminin receptor activity / Ribosomal scanning and start codon recognition / pigmentation / positive regulation of mitochondrial depolarization / Translation initiation complex formation / negative regulation of Wnt signaling pathway / fibroblast growth factor binding / Protein hydroxylation / monocyte chemotaxis / BH3 domain binding / negative regulation of translational frameshifting / regulation of adenylate cyclase-activating G protein-coupled receptor signaling pathway / SARS-CoV-1 modulates host translation machinery / positive regulation of GTPase activity / mTORC1-mediated signalling / TOR signaling / iron-sulfur cluster binding / Peptide chain elongation / regulation of cell division / cellular response to ethanol / Selenocysteine synthesis / Formation of a pool of free 40S subunits / positive regulation of intrinsic apoptotic signaling pathway by p53 class mediator / negative regulation of protein binding / Eukaryotic Translation Termination / protein serine/threonine kinase inhibitor activity / SRP-dependent cotranslational protein targeting to membrane / Response of EIF2AK4 (GCN2) to amino acid deficiency / ubiquitin ligase inhibitor activity / negative regulation of respiratory burst involved in inflammatory response / Viral mRNA Translation / endonucleolytic cleavage to generate mature 3'-end of SSU-rRNA from (SSU-rRNA, 5.8S rRNA, LSU-rRNA) / Nonsense Mediated Decay (NMD) independent of the Exon Junction Complex (EJC) / positive regulation of signal transduction by p53 class mediator / negative regulation of ubiquitin-dependent protein catabolic process / GTP hydrolysis and joining of the 60S ribosomal subunit / L13a-mediated translational silencing of Ceruloplasmin expression / Major pathway of rRNA processing in the nucleolus and cytosol / regulation of translational fidelity / positive regulation of microtubule polymerization / phagocytic cup / Nonsense Mediated Decay (NMD) enhanced by the Exon Junction Complex (EJC) / positive regulation of intrinsic apoptotic signaling pathway / spindle assembly / Protein methylation / Nuclear events stimulated by ALK signaling in cancer / endonucleolytic cleavage in ITS1 to separate SSU-rRNA from 5.8S rRNA and LSU-rRNA from tricistronic rRNA transcript (SSU-rRNA, 5.8S rRNA, LSU-rRNA) / translation regulator activity / rough endoplasmic reticulum / positive regulation of cell cycle / ribosomal small subunit export from nucleus Similarity search - Function | ||||||||||||||||||||||||
| Biological species | Homo sapiens (human) Hepacivirus hominis | ||||||||||||||||||||||||
| Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 3.2 Å | ||||||||||||||||||||||||
Authors | Iwasaki, W. / Kashiwagi, K. / Sakamoto, A. / Nishimoto, M. / Takahashi, M. / Machida, K. / Imataka, H. / Matsumoto, A. / Shichino, Y. / Iwasaki, S. ...Iwasaki, W. / Kashiwagi, K. / Sakamoto, A. / Nishimoto, M. / Takahashi, M. / Machida, K. / Imataka, H. / Matsumoto, A. / Shichino, Y. / Iwasaki, S. / Imami, K. / Ito, T. | ||||||||||||||||||||||||
| Funding support | Japan, 2items
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Citation | Journal: Proc Natl Acad Sci U S A / Year: 2025Title: Structural insights into the role of eIF3 in translation mediated by the HCV IRES. Authors: Wakana Iwasaki / Kazuhiro Kashiwagi / Ayako Sakamoto / Madoka Nishimoto / Mari Takahashi / Kodai Machida / Hiroaki Imataka / Akinobu Matsumoto / Yuichi Shichino / Shintaro Iwasaki / Koshi Imami / Takuhiro Ito / ![]() Abstract: The genomes of various RNA viruses and a subset of human genes contain structured RNA elements termed internal ribosomal entry sites (IRESs) to initiate translation in a cap-independent manner. The ...The genomes of various RNA viruses and a subset of human genes contain structured RNA elements termed internal ribosomal entry sites (IRESs) to initiate translation in a cap-independent manner. The well-studied IRES from Hepatitis C virus (HCV) binds to eukaryotic initiation factor 3 (eIF3), but how the HCV IRES harnesses eIF3 for viral translation remains unclear. Here, we determined multiple cryo-EM structures in which the HCV IRES binds simultaneously to the ribosome and eIF3, covering steps from initiation to elongation. The eIF3 core subunits are displaced from the ribosome by binding more tightly to subdomain IIIb of the HCV IRES. However, cross-linking mass spectrometry suggested that the eIF3 noncore subunits in the HCV-IRES-mediated elongation complex remain in similar positions on the ribosome to those observed in the cap-mediated initiation complex. This currently determined configuration of eIF3 core and noncore subunits reveals the mechanisms through which the HCV IRES overcomes the competition with the host mRNA and promotes viral mRNA translation by utilizing eIF3. Interestingly, cryo-EM structures also revealed that the N-terminal domain of the eIF3 c-subunit (eIF3c-NTD) binds to the large ribosomal subunit (60S) during elongation. These findings suggest that eIF3 contributes to HCV IRES-mediated translation not only during initiation but also elongation and potentially in reinitiation. The interaction between the eIF3c-NTD and the 60S ribosome is likely to occur in general translation processes as well, contributing to 60S joining or eIF3 stabilization on the elongating ribosome. | ||||||||||||||||||||||||
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Structure visualization
| Structure viewer | Molecule: Molmil Jmol/JSmol |
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Downloads & links
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Download
| PDBx/mmCIF format | 9kn5.cif.gz | 2.5 MB | Display | PDBx/mmCIF format |
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| PDB format | pdb9kn5.ent.gz | Display | PDB format | |
| PDBx/mmJSON format | 9kn5.json.gz | Tree view | PDBx/mmJSON format | |
| Others | Other downloads |
-Validation report
| Arichive directory | https://data.pdbj.org/pub/pdb/validation_reports/kn/9kn5 ftp://data.pdbj.org/pub/pdb/validation_reports/kn/9kn5 | HTTPS FTP |
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-Related structure data
| Related structure data | ![]() 62453MC ![]() 9kkfC ![]() 9kn6C ![]() 9krpC ![]() 9kzuC ![]() 9kzxC M: map data used to model this data C: citing same article ( |
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| Similar structure data | Similarity search - Function & homology F&H Search |
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Links
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Assembly
| Deposited unit | ![]()
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Components
-Protein , 4 types, 4 molecules 1ASAshSg
| #1: Protein | Mass: 16488.449 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Source: (gene. exp.) Homo sapiens (human) / Gene: EIF1AX, EIF1A, EIF4C / Production host: ![]() |
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| #2: Protein | Mass: 32883.938 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) Homo sapiens (human) / References: UniProt: P08865 |
| #33: Protein | Mass: 18004.041 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) Homo sapiens (human) / References: UniProt: P62979 |
| #34: Protein | Mass: 35115.652 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) Homo sapiens (human) / References: UniProt: P63244 |
+40S ribosomal protein ... , 30 types, 30 molecules SBSCSDSESFSGSHSISJSKSLSfSNSOSPSQSRSSSTSUSVSWSXSYSZSaSbScSdSe
-Protein/peptide , 1 types, 1 molecules Ln
| #35: Protein/peptide | Mass: 3473.451 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) Homo sapiens (human) / References: UniProt: P62945 |
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-RNA chain , 2 types, 2 molecules S2zz
| #36: RNA chain | Mass: 602777.875 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) Homo sapiens (human) / References: GenBank: 2795772166 |
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| #37: RNA chain | Mass: 107002.117 Da / Num. of mol.: 1 / Source method: obtained synthetically / Source: (synth.) Hepacivirus hominis / References: GenBank: 221513 |
-Eukaryotic translation initiation factor 3 subunit ... , 9 types, 9 molecules 3m3f3a3e3c3h3d3k3l
| #38: Protein | Mass: 42555.832 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) Homo sapiens (human) / References: UniProt: Q7L2H7 |
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| #39: Protein | Mass: 37593.645 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) Homo sapiens (human) / References: UniProt: O00303, ubiquitinyl hydrolase 1 |
| #40: Protein | Mass: 166903.781 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) Homo sapiens (human) / References: UniProt: Q14152 |
| #41: Protein | Mass: 52281.633 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) Homo sapiens (human) / References: UniProt: P60228 |
| #42: Protein | Mass: 105503.945 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) Homo sapiens (human) / References: UniProt: Q99613 |
| #43: Protein | Mass: 39979.277 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) Homo sapiens (human) / References: UniProt: O15372 |
| #44: Protein | Mass: 64060.758 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) Homo sapiens (human) / References: UniProt: O15371 |
| #45: Protein | Mass: 25083.619 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) Homo sapiens (human) / References: UniProt: Q9UBQ5 |
| #46: Protein | Mass: 66803.734 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) Homo sapiens (human) / References: UniProt: Q9Y262 |
-Non-polymers , 2 types, 10 molecules 


| #47: Chemical | | #48: Chemical | ChemComp-MG / |
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-Details
| Has ligand of interest | Y |
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| Has protein modification | N |
-Experimental details
-Experiment
| Experiment | Method: ELECTRON MICROSCOPY |
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| EM experiment | Aggregation state: PARTICLE / 3D reconstruction method: single particle reconstruction |
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Sample preparation
| Component |
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| Source (natural) |
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| Source (recombinant) | Organism: ![]() | ||||||||||||||||||||||||||||||
| Buffer solution | pH: 7.5 | ||||||||||||||||||||||||||||||
| Specimen | Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES | ||||||||||||||||||||||||||||||
| Vitrification | Instrument: FEI VITROBOT MARK IV / Cryogen name: ETHANE |
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Electron microscopy imaging
| Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |
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| Microscopy | Model: TFS KRIOS |
| Electron gun | Electron source: FIELD EMISSION GUN / Accelerating voltage: 300 kV / Illumination mode: FLOOD BEAM |
| Electron lens | Mode: BRIGHT FIELD / Nominal defocus max: 3000 nm / Nominal defocus min: 1500 nm |
| Image recording | Electron dose: 56.2 e/Å2 / Film or detector model: GATAN K3 (6k x 4k) |
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Processing
| EM software | Name: PHENIX / Version: 1.21.2_5419 / Category: model refinement |
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| CTF correction | Type: NONE |
| 3D reconstruction | Resolution: 3.2 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 46337 / Symmetry type: POINT |
| Refinement | Cross valid method: NONE |
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About Yorodumi



Homo sapiens (human)
Hepacivirus hominis
Japan, 2items
Citation










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