6baa
From Proteopedia
Cryo-EM structure of the pancreatic beta-cell KATP channel bound to ATP and glibenclamide
Structural highlights
Function[KCJ11_RAT] This receptor is controlled by G proteins. Inward rectifier potassium channels are characterized by a greater tendency to allow potassium to flow into the cell rather than out of it. Their voltage dependence is regulated by the concentration of extracellular potassium; as external potassium is raised, the voltage range of the channel opening shifts to more positive voltages. The inward rectification is mainly due to the blockage of outward current by internal magnesium. Can be blocked by extracellular barium. Can form cardiac and smooth muscle-type KATP channels with ABCC9. KCNJ11 forms the channel pore while ABCC9 is required for activation and regulation (By similarity). [ABCC8_CRICR] Subunit of the beta-cell ATP-sensitive potassium channel (KATP). Regulator of ATP-sensitive potassium channels and insulin release.[UniProtKB:Q09428] Publication Abstract from PubMedSulfonylureas are anti-diabetic medications that act by inhibiting pancreatic KATP channels composed of SUR1 and Kir6.2. The mechanism by which these drugs interact with and inhibit the channel has been extensively investigated, yet it remains unclear where the drug binding pocket resides. Here, we present a cryo-EM structure of a hamster SUR1/rat Kir6.2 channel bound to a high-affinity sulfonylurea drug glibenclamide and ATP at 3.63 A resolution, which reveals unprecedented details of the ATP and glibenclamide binding sites. Importantly, the structure shows for the first time that glibenclamide is lodged in the transmembrane bundle of the SUR1-ABC core connected to the first nucleotide binding domain near the inner leaflet of the lipid bilayer. Mutation of residues predicted to interact with glibenclamide in our model led to reduced sensitivity to glibenclamide. Our structure provides novel mechanistic insights of how sulfonylureas and ATP interact with the KATP channel complex to inhibit channel activity. Anti-diabetic drug binding site in a mammalian KATP channel revealed by Cryo-EM.,Martin GM, Kandasamy B, DiMaio F, Yoshioka C, Shyng SL Elife. 2017 Oct 24;6. pii: e31054. doi: 10.7554/eLife.31054. PMID:29035201[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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