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- EMDB-18457: Connexin-32 hemichannel upon addition of 2-aminoetoxydiphenyl borate -
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Open data
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Basic information
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Title | Connexin-32 hemichannel upon addition of 2-aminoetoxydiphenyl borate | |||||||||
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![]() | cell communication / channel / MEMBRANE PROTEIN | |||||||||
Function / homology | ![]() purine ribonucleotide transport / epididymis development / Oligomerization of connexins into connexons / Transport of connexins along the secretory pathway / gap junction assembly / connexin complex / gap junction channel activity / Gap junction assembly / lateral plasma membrane / nervous system development ...purine ribonucleotide transport / epididymis development / Oligomerization of connexins into connexons / Transport of connexins along the secretory pathway / gap junction assembly / connexin complex / gap junction channel activity / Gap junction assembly / lateral plasma membrane / nervous system development / cell-cell signaling / endoplasmic reticulum membrane / identical protein binding Similarity search - Function | |||||||||
Biological species | ![]() | |||||||||
Method | single particle reconstruction / cryo EM / Resolution: 3.18 Å | |||||||||
![]() | Lavriha P / Korkhov VM / Han Y | |||||||||
Funding support | ![]()
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![]() | ![]() Title: Mechanism of connexin channel inhibition by mefloquine and 2-aminoethoxydiphenyl borate. Authors: Pia Lavriha / Yufei Han / Xinyue Ding / Dina Schuster / Chao Qi / Anand Vaithia / Paola Picotti / Volodymyr M Korkhov / ![]() ![]() Abstract: Gap junction intercellular communication (GJIC) between two adjacent cells involves direct exchange of cytosolic ions and small molecules via connexin gap junction channels (GJCs). Connexin GJCs have ...Gap junction intercellular communication (GJIC) between two adjacent cells involves direct exchange of cytosolic ions and small molecules via connexin gap junction channels (GJCs). Connexin GJCs have emerged as drug targets, with small molecule connexin inhibitors considered a viable therapeutic strategy in several diseases. The molecular mechanisms of GJC inhibition by known small molecule connexin inhibitors remain unknown, preventing the development of more potent and connexin-specific therapeutics. Here we show that two GJC inhibitors, mefloquine (MFQ) and 2-aminoethoxydiphenyl borate (2APB) bind to Cx32 and block dye permeation across Cx32 hemichannels (HCs) and GJCs. Cryo-EM analysis shows that 2APB binds to "site A", close to the N-terminal gating helix of Cx32 GJC, restricting the entrance to the channel pore. In contrast, MFQ binds to a distinct "site M", deeply buried within the pore. MFQ binding to this site modifies the electrostatic properties of Cx32 pore. Mutagenesis of V37, a key residue located in the site M, renders Cx32 HCs and GJCs insensitive to MFQ-mediated inhibition. Moreover, our cryo-EM analysis, mutagenesis and activity assays show that MFQ targets the M site in Cx43 GJC similarly to Cx32. Taken together, our results point to a conserved inhibitor binding site in connexin channels, opening a new route for development of specific drugs targeting connexins. | |||||||||
History |
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Structure visualization
Supplemental images |
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Downloads & links
-EMDB archive
Map data | ![]() | 29.4 MB | ![]() | |
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Header (meta data) | ![]() ![]() | 15.9 KB 15.9 KB | Display Display | ![]() |
Images | ![]() | 74.7 KB | ||
Masks | ![]() | 216 MB | ![]() | |
Filedesc metadata | ![]() | 6 KB | ||
Others | ![]() ![]() | 170 MB 170.2 MB | ||
Archive directory | ![]() ![]() | HTTPS FTP |
-Related structure data
Related structure data | ![]() 8qk6MC ![]() 8qjfC ![]() 8qjhC ![]() 8qkiC ![]() 8qkoC M: atomic model generated by this map C: citing same article ( |
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Similar structure data | Similarity search - Function & homology ![]() |
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Links
EMDB pages | ![]() ![]() |
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Map
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Projections & slices | Image control
Images are generated by Spider. | ||||||||||||||||||||||||||||||||||||
Voxel size | X=Y=Z: 0.65 Å | ||||||||||||||||||||||||||||||||||||
Density |
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Symmetry | Space group: 1 | ||||||||||||||||||||||||||||||||||||
Details | EMDB XML:
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-Supplemental data
-Mask #1
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Density Histograms |
-Half map: half1
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Annotation | half1 | ||||||||||||
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Density Histograms |
-Half map: #1
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Density Histograms |
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Sample components
-Entire : Connexin-32 gap junction channel in complex with 2-aminoethoxydip...
Entire | Name: Connexin-32 gap junction channel in complex with 2-aminoethoxydipheniyl borate |
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Components |
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-Supramolecule #1: Connexin-32 gap junction channel in complex with 2-aminoethoxydip...
Supramolecule | Name: Connexin-32 gap junction channel in complex with 2-aminoethoxydipheniyl borate type: complex / ID: 1 / Parent: 0 / Macromolecule list: #1 |
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Source (natural) | Organism: ![]() |
-Macromolecule #1: Gap junction beta-1 protein
Macromolecule | Name: Gap junction beta-1 protein / type: protein_or_peptide / ID: 1 / Number of copies: 6 / Enantiomer: LEVO |
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Source (natural) | Organism: ![]() |
Molecular weight | Theoretical: 32.065533 KDa |
Recombinant expression | Organism: ![]() |
Sequence | String: MNWTGLYTLL SGVNRHSTAI GRVWLSVIFI FRIMVLVVAA ESVWGDEKSS FICNTLQPGC NSVCYDQFFP ISHVRLWSLQ LILVSTPAL LVAMHVAHQQ HIEKKMLRLE GHGDPLHLEE VKRHKVHISG TLWWTYVISV VFRLLFEAVF MYVFYLLYPG Y AMVRLVKC ...String: MNWTGLYTLL SGVNRHSTAI GRVWLSVIFI FRIMVLVVAA ESVWGDEKSS FICNTLQPGC NSVCYDQFFP ISHVRLWSLQ LILVSTPAL LVAMHVAHQQ HIEKKMLRLE GHGDPLHLEE VKRHKVHISG TLWWTYVISV VFRLLFEAVF MYVFYLLYPG Y AMVRLVKC DVYPCPNTVD CFVSRPTEKT VFTVFMLAAS GICIILNVAE VVYLIIRACA RRAQRRSNPP SRKGSGFGHR LS PEYKQNE INKLLSEQDG SLKDILRRSP GTGAGLAEKS DRCSAC UniProtKB: Gap junction beta-1 protein |
-Macromolecule #2: CHOLESTEROL
Macromolecule | Name: CHOLESTEROL / type: ligand / ID: 2 / Number of copies: 6 / Formula: CLR |
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Molecular weight | Theoretical: 386.654 Da |
Chemical component information | ![]() ChemComp-CLR: |
-Experimental details
-Structure determination
Method | cryo EM |
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![]() | single particle reconstruction |
Aggregation state | particle |
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Sample preparation
Concentration | 5 mg/mL | |||||||||
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Buffer | pH: 8 Component:
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Vitrification | Cryogen name: ETHANE / Chamber humidity: 100 % / Chamber temperature: 277 K / Instrument: FEI VITROBOT MARK IV |
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Electron microscopy
Microscope | FEI TITAN KRIOS |
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Image recording | Film or detector model: GATAN K3 (6k x 4k) / Average electron dose: 50.0 e/Å2 |
Electron beam | Acceleration voltage: 300 kV / Electron source: ![]() |
Electron optics | Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD / Nominal defocus max: 2.5 µm / Nominal defocus min: 0.5 µm / Nominal magnification: 130000 |
Sample stage | Cooling holder cryogen: NITROGEN |
Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |