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| Title | Cryo-EM structures of Kv1.2 potassium channels, conducting and non-conducting. |
|---|---|
| Journal, issue, pages | bioRxiv, Year 2024 |
| Publish date | Mar 19, 2024 |
 Authors | Yangyu Wu / Yangyang Yan / Youshan Yang / Shumin Bian / Alberto Rivetta / Ken Allen / Fred J Sigworth /  |
| PubMed Abstract | We present near-atomic-resolution cryo-EM structures of the mammalian voltage-gated potassium channel Kv1.2 in open, C-type inactivated, toxin-blocked and sodium-bound states at 3.2 Å, 2.5 Å, 3.2 ...We present near-atomic-resolution cryo-EM structures of the mammalian voltage-gated potassium channel Kv1.2 in open, C-type inactivated, toxin-blocked and sodium-bound states at 3.2 Å, 2.5 Å, 3.2 Å, and 2.9Å. These structures, all obtained at nominally zero membrane potential in detergent micelles, reveal distinct ion-occupancy patterns in the selectivity filter. The first two structures are very similar to those reported in the related Shaker channel and the much-studied Kv1.2-2.1 chimeric channel. On the other hand, two new structures show unexpected patterns of ion occupancy. First, the toxin α-Dendrotoxin, like Charybdotoxin, is seen to attach to the negatively-charged channel outer mouth, and a lysine residue penetrates into the selectivity filter, with the terminal amine coordinated by carbonyls, partially disrupting the outermost ion-binding site. In the remainder of the filter two densities of bound ions are observed, rather than three as observed with other toxin-blocked Kv channels. Second, a structure of Kv1.2 in Na solution does not show collapse or destabilization of the selectivity filter, but instead shows an intact selectivity filter with ion density in each binding site. We also attempted to image the C-type inactivated Kv1.2 W366F channel in Na solution, but the protein conformation was seen to be highly variable and only a low-resolution structure could be obtained. These findings present new insights into the stability of the selectivity filter and the mechanism of toxin block of this intensively studied, voltage-gated potassium channel. |
 External links | bioRxiv / PubMed:37398110 / PubMed Central |
| Methods | EM (single particle) |
| Resolution | 2.55 - 3.2 Å |
| Structure data | EMDB-43131, PDB-8vc3: EMDB-43133, PDB-8vc4: EMDB-43134, PDB-8vc6: EMDB-43136, PDB-8vch: |
| Chemicals |  ChemComp-K: |
| Source |
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 Keywords | MEMBRANE PROTEIN / Ion Channel / Toxin bound / Blocker / Sodium bound / Potassium / mutant / C-type inactivated |
Komagataella pastoris (fungus)
dendroaspis angusticeps (eastern green mamba)
rattus norvegicus (Norway rat)