8QKO
Connexin-43 gap junction channel in complex with mefloquine
Summary for 8QKO
| Entry DOI | 10.2210/pdb8qko/pdb |
| EMDB information | 18468 |
| Descriptor | Gap junction alpha-1 protein (1 entity in total) |
| Functional Keywords | connexin, gap junction channel, complex, mefloquine, membrane protein |
| Biological source | Homo sapiens (human) |
| Total number of polymer chains | 12 |
| Total formula weight | 516736.03 |
| Authors | Lavriha, P.,Korkhov, V.M.,Han, Y. (deposition date: 2023-09-16, release date: 2024-09-25, Last modification date: 2025-01-22) |
| Primary citation | Lavriha, P.,Han, Y.,Ding, X.,Schuster, D.,Qi, C.,Vaithia, A.,Picotti, P.,Korkhov, V.M. Mechanism of connexin channel inhibition by mefloquine and 2-aminoethoxydiphenyl borate. Plos One, 19:e0315510-e0315510, 2024 Cited by PubMed 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 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. PubMed: 39739741DOI: 10.1371/journal.pone.0315510 PDB entries with the same primary citation |
| Experimental method | ELECTRON MICROSCOPY (3.73 Å) |
Structure validation
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