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Yorodumi- PDB-9qwx: Cryo-EM structure of the human UBR4/KCMF1/CALM1 complex (N-term f... -
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Open data
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Basic information
| Entry | Database: PDB / ID: 9qwx | |||||||||
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| Title | Cryo-EM structure of the human UBR4/KCMF1/CALM1 complex (N-term focused refinement) | |||||||||
Components | E3 ubiquitin-protein ligase UBR4 | |||||||||
Keywords | LIGASE / Ubiquitin ligase / protein quality control | |||||||||
| Function / homology | Function and homology informationnegative regulation of HRI-mediated signaling / ubiquitin-dependent protein catabolic process via the N-end rule pathway / protein K27-linked ubiquitination / cytoplasm protein quality control by the ubiquitin-proteasome system / protein branched polyubiquitination / negative regulation of fatty acid biosynthetic process / endosome organization / cytoplasm protein quality control / protein K11-linked ubiquitination / tertiary granule membrane ...negative regulation of HRI-mediated signaling / ubiquitin-dependent protein catabolic process via the N-end rule pathway / protein K27-linked ubiquitination / cytoplasm protein quality control by the ubiquitin-proteasome system / protein branched polyubiquitination / negative regulation of fatty acid biosynthetic process / endosome organization / cytoplasm protein quality control / protein K11-linked ubiquitination / tertiary granule membrane / ficolin-1-rich granule membrane / protein K48-linked ubiquitination / specific granule membrane / positive regulation of autophagy / RING-type E3 ubiquitin transferase / ubiquitin-protein transferase activity / ubiquitin protein ligase activity / Antigen processing: Ubiquitination & Proteasome degradation / response to oxidative stress / ubiquitin-dependent protein catabolic process / proteasome-mediated ubiquitin-dependent protein catabolic process / calmodulin binding / endosome / protein stabilization / centrosome / Neutrophil degranulation / zinc ion binding / nucleoplasm / membrane / plasma membrane / cytoplasm / cytosol Similarity search - Function | |||||||||
| Biological species | Homo sapiens (human) | |||||||||
| Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 3.6 Å | |||||||||
Authors | Grabarczyk, D.B. / Clausen, T. | |||||||||
| Funding support | Austria, European Union, 2items
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Citation | Journal: Science / Year: 2025Title: Architecture of the UBR4 complex, a giant E4 ligase central to eukaryotic protein quality control. Authors: Daniel B Grabarczyk / Julian F Ehrmann / Paul Murphy / Woo Seok Yang / Robert Kurzbauer / Lillie E Bell / Luiza Deszcz / Jana Neuhold / Alexander Schleiffer / Alexandra Shulkina / Juyeon Lee ...Authors: Daniel B Grabarczyk / Julian F Ehrmann / Paul Murphy / Woo Seok Yang / Robert Kurzbauer / Lillie E Bell / Luiza Deszcz / Jana Neuhold / Alexander Schleiffer / Alexandra Shulkina / Juyeon Lee / Jin Seok Shin / Anton Meinhart / Gijs A Versteeg / Eszter Zavodszky / Hyun Kyu Song / Ramanujan S Hegde / Tim Clausen / ![]() Abstract: Eukaryotic cells have evolved sophisticated quality control mechanisms to eliminate aggregation-prone proteins that compromise cellular health. Central to this defense is the ubiquitin-proteasome ...Eukaryotic cells have evolved sophisticated quality control mechanisms to eliminate aggregation-prone proteins that compromise cellular health. Central to this defense is the ubiquitin-proteasome system, where UBR4 acts as an essential E4 ubiquitin ligase, amplifying degradation marks on defective proteins. Cryo-electron microscopy analysis of UBR4 in complex with its cofactors KCMF1 and CALM1 reveals a massive 1.3-megadalton ring structure, featuring a central substrate-binding arena and flexibly attached catalytic units. Our structure shows how UBR4 binds substrate and extends lysine-48-specific ubiquitin chains. Efficient substrate targeting depends on both preubiquitination and specific N-degrons, with KCMF1 acting as a key substrate filter. The architecture of the E4 megacomplex is conserved across eukaryotes, but species-specific adaptations allow UBR4 to perform its precisely tuned quality control function in diverse cellular environments. | |||||||||
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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 | 9qwx.cif.gz | 583 KB | Display | PDBx/mmCIF format |
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| PDB format | pdb9qwx.ent.gz | 397.4 KB | Display | PDB format |
| PDBx/mmJSON format | 9qwx.json.gz | Tree view | PDBx/mmJSON format | |
| Others | Other downloads |
-Validation report
| Summary document | 9qwx_validation.pdf.gz | 1.5 MB | Display | wwPDB validaton report |
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| Full document | 9qwx_full_validation.pdf.gz | 1.6 MB | Display | |
| Data in XML | 9qwx_validation.xml.gz | 79.8 KB | Display | |
| Data in CIF | 9qwx_validation.cif.gz | 125 KB | Display | |
| Arichive directory | https://data.pdbj.org/pub/pdb/validation_reports/qw/9qwx ftp://data.pdbj.org/pub/pdb/validation_reports/qw/9qwx | HTTPS FTP |
-Related structure data
| Related structure data | ![]() 53430MC ![]() 9jniC ![]() 9lgsC ![]() 9qt9C ![]() 9qwsC ![]() 9qwuC ![]() 9qwzC ![]() 9qx0C ![]() 9qx1C ![]() 9qx2C ![]() 9qx5C ![]() 9upzC 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
| #1: Protein | Mass: 575844.000 Da / Num. of mol.: 2 Source method: isolated from a genetically manipulated source Source: (gene. exp.) Homo sapiens (human) / Gene: UBR4, KIAA0462, KIAA1307, RBAF600 / Production host: Trichoplusia ni (cabbage looper)References: UniProt: Q5T4S7, RING-type E3 ubiquitin transferase Has protein modification | N | |
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-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 UBR4/KCMF1/CALM1 complex / Type: COMPLEX / Entity ID: all / Source: RECOMBINANT |
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| Molecular weight | Experimental value: NO |
| Source (natural) | Organism: Homo sapiens (human) |
| Source (recombinant) | Organism: Trichoplusia ni (cabbage looper) |
| Buffer solution | pH: 7.5 |
| Specimen | Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES |
| Vitrification | 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: 2000 nm / Nominal defocus min: 800 nm |
| Image recording | Electron dose: 50 e/Å2 / Film or detector model: FEI FALCON IV (4k x 4k) |
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Processing
| EM software | Name: PHENIX / Category: model refinement | ||||||||||||||||||||||||
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| CTF correction | Type: PHASE FLIPPING AND AMPLITUDE CORRECTION | ||||||||||||||||||||||||
| Symmetry | Point symmetry: C2 (2 fold cyclic) | ||||||||||||||||||||||||
| 3D reconstruction | Resolution: 3.6 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 75153 / Symmetry type: POINT | ||||||||||||||||||||||||
| Refinement | Highest resolution: 3.6 Å Stereochemistry target values: REAL-SPACE (WEIGHTED MAP SUM AT ATOM CENTERS) | ||||||||||||||||||||||||
| Refine LS restraints |
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About Yorodumi



Homo sapiens (human)
Austria, European Union, 2items
Citation




























PDBj
Trichoplusia ni (cabbage looper)
FIELD EMISSION GUN