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Yorodumi- PDB-9kkf: Structure of the human 40S ribosome complexed with HCV IRES and eIF3 -
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Open data
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Basic information
| Entry | Database: PDB / ID: 9kkf | ||||||||||||||||||||||||
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| Title | Structure of the human 40S ribosome complexed with HCV IRES and eIF3 | ||||||||||||||||||||||||
Components |
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Keywords | RIBOSOME / HCV IRES | ||||||||||||||||||||||||
| Function / homology | Function and homology informationpositive regulation of mRNA binding / 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 / eukaryotic translation initiation factor 3 complex / cytoplasmic translational initiation ...positive regulation of mRNA binding / 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 / eukaryotic translation initiation factor 3 complex / cytoplasmic translational initiation / multi-eIF complex / eukaryotic 43S preinitiation complex / mRNA cap binding / eukaryotic 48S preinitiation complex / oxidized pyrimidine DNA binding / response to TNF agonist / negative regulation of endoplasmic reticulum unfolded protein response / positive regulation of base-excision repair / positive regulation of respiratory burst involved in inflammatory response / positive regulation of intrinsic apoptotic signaling pathway in response to DNA damage / positive regulation of gastrulation / protein tyrosine kinase inhibitor activity / positive regulation of endodeoxyribonuclease activity / nucleolus organization / IRE1-RACK1-PP2A complex / positive regulation of Golgi to plasma membrane protein transport / TNFR1-mediated ceramide production / metal-dependent deubiquitinase activity / negative regulation of DNA repair / nuclear-transcribed mRNA catabolic process, nonsense-mediated decay / negative regulation of RNA splicing / regulation of translational initiation / supercoiled DNA binding / NF-kappaB complex / neural crest cell differentiation / oxidized purine DNA binding / cysteine-type endopeptidase activator activity involved in apoptotic process / positive regulation of ubiquitin-protein transferase activity / negative regulation of intrinsic apoptotic signaling pathway in response to hydrogen peroxide / negative regulation of bicellular tight junction assembly / regulation of establishment of cell polarity / ubiquitin-like protein conjugating enzyme binding / rRNA modification in the nucleus and cytosol / negative regulation of phagocytosis / erythrocyte homeostasis / Formation of the ternary complex, and subsequently, the 43S complex / cytoplasmic side of rough endoplasmic reticulum membrane / negative regulation of ubiquitin protein ligase activity / protein kinase A binding / laminin receptor activity / ion channel inhibitor activity / Ribosomal scanning and start codon recognition / pigmentation / Translation initiation complex formation / positive regulation of mitochondrial depolarization / positive regulation of T cell receptor signaling pathway / fibroblast growth factor binding / negative regulation of Wnt signaling pathway / monocyte chemotaxis / TOR signaling / negative regulation of translational frameshifting / BH3 domain binding / positive regulation of activated T cell proliferation / Protein hydroxylation / SARS-CoV-1 modulates host translation machinery / iron-sulfur cluster binding / regulation of adenylate cyclase-activating G protein-coupled receptor signaling pathway / regulation of cell division / cellular response to ethanol / mTORC1-mediated signalling / Peptide chain elongation / Selenocysteine synthesis / Formation of a pool of free 40S subunits / positive regulation of intrinsic apoptotic signaling pathway by p53 class mediator / endonucleolytic cleavage to generate mature 3'-end of SSU-rRNA from (SSU-rRNA, 5.8S rRNA, LSU-rRNA) / Eukaryotic Translation Termination / positive regulation of GTPase activity / negative regulation of ubiquitin-dependent protein catabolic process / 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 / Viral mRNA Translation / negative regulation of respiratory burst involved in inflammatory response / positive regulation of signal transduction by p53 class mediator / Nonsense Mediated Decay (NMD) independent of the Exon Junction Complex (EJC) / 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 / phagocytic cup / Nonsense Mediated Decay (NMD) enhanced by the Exon Junction Complex (EJC) / negative regulation of protein binding / Nuclear events stimulated by ALK signaling in cancer / Protein methylation / positive regulation of intrinsic apoptotic signaling pathway / spindle assembly / 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) / laminin binding / positive regulation of cell cycle Similarity search - Function | ||||||||||||||||||||||||
| Biological species | Homo sapiens (human) Hepacivirus hominis | ||||||||||||||||||||||||
| Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 3.3 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 | 9kkf.cif.gz | 2.5 MB | Display | PDBx/mmCIF format |
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| PDB format | pdb9kkf.ent.gz | Display | PDB format | |
| PDBx/mmJSON format | 9kkf.json.gz | Tree view | PDBx/mmJSON format | |
| Others | Other downloads |
-Validation report
| Summary document | 9kkf_validation.pdf.gz | 1.8 MB | Display | wwPDB validaton report |
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| Full document | 9kkf_full_validation.pdf.gz | 1.9 MB | Display | |
| Data in XML | 9kkf_validation.xml.gz | 223.6 KB | Display | |
| Data in CIF | 9kkf_validation.cif.gz | 382.5 KB | Display | |
| Arichive directory | https://data.pdbj.org/pub/pdb/validation_reports/kk/9kkf ftp://data.pdbj.org/pub/pdb/validation_reports/kk/9kkf | HTTPS FTP |
-Related structure data
| Related structure data | ![]() 62386MC ![]() 9kn5C ![]() 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 , 3 types, 3 molecules SAshSg
| #1: Protein | Mass: 32883.938 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) Homo sapiens (human) / References: UniProt: P08865 |
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| #32: Protein | Mass: 18004.041 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) Homo sapiens (human) / References: UniProt: P62979 |
| #33: 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
| #34: 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
| #35: 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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| #36: 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
| #37: 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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| #38: 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 |
| #39: Protein | Mass: 166903.781 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) Homo sapiens (human) / References: UniProt: Q14152 |
| #40: Protein | Mass: 52281.633 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) Homo sapiens (human) / References: UniProt: P60228 |
| #41: Protein | Mass: 105503.945 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) Homo sapiens (human) / References: UniProt: Q99613 |
| #42: Protein | Mass: 39979.277 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) Homo sapiens (human) / References: UniProt: O15372 |
| #43: Protein | Mass: 64060.758 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) Homo sapiens (human) / References: UniProt: O15371 |
| #44: Protein | Mass: 25083.619 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) Homo sapiens (human) / References: UniProt: Q9UBQ5 |
| #45: 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 


| #46: Chemical | | #47: 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 | Name: Human translational initiation complex with HCV IRES and eIF3 Type: RIBOSOME / Entity ID: #1-#45 / Source: NATURAL |
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| Source (natural) | Organism: Homo sapiens (human) |
| Buffer solution | pH: 7.5 |
| Specimen | Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES |
| Specimen support | Grid material: COPPER / Grid mesh size: 300 divisions/in. / Grid type: Quantifoil R1.2/1.3 |
| 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: 3.3 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 24675 / Symmetry type: POINT |
| Refinement | Cross valid method: NONE |
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About Yorodumi



Homo sapiens (human)
Hepacivirus hominis
Japan, 2items
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