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- PDB-8rmn: Cryo-EM structure of a dimer of decameric human CALHM4 in complex... -
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Open data
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Basic information
Entry | Database: PDB / ID: 8rmn | ||||||
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Title | Cryo-EM structure of a dimer of decameric human CALHM4 in complex with synthetic nanobody SbC4 | ||||||
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![]() | MEMBRANE PROTEIN / ion channel / large pore channels / sybody / CALHM | ||||||
Function / homology | Calcium homeostasis modulator family / Calcium homeostasis modulator / monoatomic cation channel activity / membrane / Calcium homeostasis modulator protein 4![]() | ||||||
Biological species | ![]() synthetic construct (others) | ||||||
Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 3.8 Å | ||||||
![]() | Peter, M. / Drozdzyk, K. / Dutzler, R. | ||||||
Funding support | ![]()
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![]() | ![]() Title: Structural features of heteromeric channels composed of CALHM2 and CALHM4 paralogs. Authors: Katarzyna Drożdżyk / Martina Peter / Raimund Dutzler / ![]() Abstract: The CALHM proteins constitute a family of large pore channels that contains six closely related paralogs in humans. Two family members, CALHM1 and 3, have been associated with the release of ATP ...The CALHM proteins constitute a family of large pore channels that contains six closely related paralogs in humans. Two family members, CALHM1 and 3, have been associated with the release of ATP during taste sensation. Both proteins form heteromeric channels that activate at positive potential and decreased extracellular Ca concentration. Although the structures of several family members displayed large oligomeric organizations of different size, their function has in most cases remained elusive. Our previous study has identified the paralogs CALHM2, 4 and, 6 to be highly expressed in the placenta and defined their structural properties as membrane proteins exhibiting features of large pore channels with unknown activation properties (Drożdżyk et al., 2020). Here, we investigated whether these placental paralogs would form heteromers and characterized heteromeric complexes consisting of CALHM2 and CALHM4 subunits using specific binders as fiducial markers. Both proteins assemble with different stoichiometries with the largest population containing CALHM2 as the predominant component. In these oligomers, the subunits segregate and reside in their preferred conformation found in homomeric channels. Our study has thus revealed the properties that govern the formation of CALHM heteromers in a process of potential relevance in a cellular context. | ||||||
History |
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Structure visualization
Structure viewer | Molecule: ![]() ![]() |
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Downloads & links
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Download
PDBx/mmCIF format | ![]() | 1.2 MB | Display | ![]() |
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PDB format | ![]() | 999.2 KB | Display | ![]() |
PDBx/mmJSON format | ![]() | Tree view | ![]() | |
Others | ![]() |
-Validation report
Summary document | ![]() | 1.8 MB | Display | ![]() |
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Full document | ![]() | 1.8 MB | Display | |
Data in XML | ![]() | 181.3 KB | Display | |
Data in CIF | ![]() | 256 KB | Display | |
Arichive directory | ![]() ![]() | HTTPS FTP |
-Related structure data
Related structure data | ![]() 19365MC ![]() 8rmkC ![]() 8rmlC ![]() 8rmmC M: map data used to model this data C: citing same article ( |
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Similar structure data | Similarity search - Function & homology ![]() |
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Links
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Assembly
Deposited unit | ![]()
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Components
#1: Protein | Mass: 35981.656 Da / Num. of mol.: 20 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() #2: Antibody | Mass: 15613.268 Da / Num. of mol.: 20 Source method: isolated from a genetically manipulated source Source: (gene. exp.) synthetic construct (others) / Production host: ![]() ![]() |
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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: Complex of CALHM4 channel with synthetic nanobody SbC4 Type: COMPLEX / Entity ID: all / Source: RECOMBINANT |
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Molecular weight | Value: 1.03 MDa / Experimental value: NO |
Source (natural) | Organism: ![]() |
Source (recombinant) | Organism: ![]() |
Buffer solution | pH: 7.6 |
Specimen | Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES |
Vitrification | Cryogen name: ETHANE-PROPANE |
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Electron microscopy imaging
Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |
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Microscopy | Model: FEI TITAN KRIOS |
Electron gun | Electron source: ![]() |
Electron lens | Mode: BRIGHT FIELD / Nominal defocus max: 2400 nm / Nominal defocus min: 1000 nm |
Image recording | Electron dose: 70 e/Å2 / Film or detector model: GATAN K3 BIOQUANTUM (6k x 4k) |
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Processing
CTF correction | Type: PHASE FLIPPING AND AMPLITUDE CORRECTION | ||||||||||||||||||||||||
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Symmetry | Point symmetry: D10 (2x10 fold dihedral) | ||||||||||||||||||||||||
3D reconstruction | Resolution: 3.8 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 52248 / Symmetry type: POINT | ||||||||||||||||||||||||
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