+Open data
-Basic information
Entry | Database: PDB / ID: 7n0k | ||||||
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Title | Cryo-EM structure of TACAN in the apo form (TMEM120A) | ||||||
Components | Ion channel TACAN | ||||||
Keywords | MEMBRANE PROTEIN / lipid metabolism / coenzyme A | ||||||
Function / homology | Function and homology information protein heterooligomerization / nuclear inner membrane / fat cell differentiation / detection of mechanical stimulus involved in sensory perception of pain / monoatomic ion transmembrane transport / protein homooligomerization / monoatomic ion channel activity / membrane / plasma membrane Similarity search - Function | ||||||
Biological species | Mus musculus (house mouse) | ||||||
Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 3.5 Å | ||||||
Authors | Niu, Y. / Tao, X. / MacKinnon, R. | ||||||
Funding support | United States, 1items
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Citation | Journal: Elife / Year: 2021 Title: Analysis of the mechanosensor channel functionality of TACAN. Authors: Yiming Niu / Xiao Tao / George Vaisey / Paul Dominic B Olinares / Hanan Alwaseem / Brian T Chait / Roderick MacKinnon / Abstract: Mechanosensitive ion channels mediate transmembrane ion currents activated by mechanical forces. A mechanosensitive ion channel called TACAN was recently reported. We began to study TACAN with the ...Mechanosensitive ion channels mediate transmembrane ion currents activated by mechanical forces. A mechanosensitive ion channel called TACAN was recently reported. We began to study TACAN with the intent to understand how it senses mechanical forces and functions as an ion channel. Using cellular patch-recording methods, we failed to identify mechanosensitive ion channel activity. Using membrane reconstitution methods, we found that TACAN, at high protein concentrations, produces heterogeneous conduction levels that are not mechanosensitive and are most consistent with disruptions of the lipid bilayer. We determined the structure of TACAN using single-particle cryo-electron microscopy and observed that it is a symmetrical dimeric transmembrane protein. Each protomer contains an intracellular-facing cleft with a coenzyme A cofactor, confirmed by mass spectrometry. The TACAN protomer is related in three-dimensional structure to a fatty acid elongase, ELOVL7. Whilst its physiological function remains unclear, we anticipate that TACAN is not a mechanosensitive ion channel. | ||||||
History |
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-Structure visualization
Movie |
Movie viewer |
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Structure viewer | Molecule: MolmilJmol/JSmol |
-Downloads & links
-Download
PDBx/mmCIF format | 7n0k.cif.gz | 121.4 KB | Display | PDBx/mmCIF format |
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PDB format | pdb7n0k.ent.gz | 94.2 KB | Display | PDB format |
PDBx/mmJSON format | 7n0k.json.gz | Tree view | PDBx/mmJSON format | |
Others | Other downloads |
-Validation report
Summary document | 7n0k_validation.pdf.gz | 791.7 KB | Display | wwPDB validaton report |
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Full document | 7n0k_full_validation.pdf.gz | 798.6 KB | Display | |
Data in XML | 7n0k_validation.xml.gz | 23.3 KB | Display | |
Data in CIF | 7n0k_validation.cif.gz | 32 KB | Display | |
Arichive directory | https://data.pdbj.org/pub/pdb/validation_reports/n0/7n0k ftp://data.pdbj.org/pub/pdb/validation_reports/n0/7n0k | HTTPS FTP |
-Related structure data
Related structure data | 24107MC 7n0lC M: map data used to model this data C: citing same article (ref.) |
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Similar structure data |
-Links
-Assembly
Deposited unit |
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1 |
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-Components
#1: Protein | Mass: 40797.297 Da / Num. of mol.: 2 Source method: isolated from a genetically manipulated source Source: (gene. exp.) Mus musculus (house mouse) / Gene: Tmem120a, Net29, Tacan / Production host: Homo sapiens (human) / References: UniProt: Q8C1E7 |
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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 |
-Sample preparation
Component | Name: Homo-dimeric assembly of wild type TACAN(TMEM120A) / Type: COMPLEX / Entity ID: all / Source: RECOMBINANT |
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Molecular weight | Units: KILODALTONS/NANOMETER / Experimental value: NO |
Source (natural) | Organism: Mus musculus (house mouse) |
Source (recombinant) | Organism: Homo sapiens (human) |
Buffer solution | pH: 7.4 Details: 20 mM HEPES pH 7.4, 250 mM NaCl, and 0.06% Digitonin (w/v) |
Specimen | Conc.: 6 mg/ml / Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES |
Specimen support | Grid material: GOLD / Grid mesh size: 400 divisions/in. / Grid type: Quantifoil R1.2/1.3 |
Vitrification | Instrument: FEI VITROBOT MARK IV / Cryogen name: ETHANE / Humidity: 95 % / Chamber temperature: 298 K |
-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: FIELD EMISSION GUN / Accelerating voltage: 300 kV / Illumination mode: FLOOD BEAM |
Electron lens | Mode: DARK FIELD / C2 aperture diameter: 100 µm |
Specimen holder | Cryogen: NITROGEN / Specimen holder model: FEI TITAN KRIOS AUTOGRID HOLDER |
Image recording | Average exposure time: 10 sec. / Electron dose: 75.4 e/Å2 / Film or detector model: GATAN K2 SUMMIT (4k x 4k) / Num. of grids imaged: 1 |
-Processing
Software | Name: PHENIX / Version: dev_3751: / Classification: refinement | ||||||||||||||||||||||||||||||||||||||||||||||||||||
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EM software |
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CTF correction | Type: NONE | ||||||||||||||||||||||||||||||||||||||||||||||||||||
Symmetry | Point symmetry: C2 (2 fold cyclic) | ||||||||||||||||||||||||||||||||||||||||||||||||||||
3D reconstruction | Resolution: 3.5 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 110090 / Symmetry type: POINT | ||||||||||||||||||||||||||||||||||||||||||||||||||||
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