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Publication Abstract from PubMed

The gate at the pore-forming domain of potassium channels is allosterically controlled by a stimulus-sensing domain. Using Cd(2)(+) as a probe, we examined the structural elements responsible for gating in an inward-rectifier K(+) channel (Kir3.2). One of four endogenous cysteines facing the cytoplasm contributes to a high-affinity site for inhibition by internal Cd(2)(+). Crystal structure of its cytoplasmic domain in complex with Cd(2)(+) reveals that octahedral coordination geometry supports the high-affinity binding. This mode of action causes the tethering of the N-terminus to CD loop in the stimulus-sensing domain, suggesting that their conformational changes participate in gating and Cd(2)(+) inhibits Kir3.2 by trapping the conformation in the closed state like "inverse agonist".

Inverse agonist-like action of cadmium on G-protein-gated inward-rectifier K(+) channels.,Inanobe A, Matsuura T, Nakagawa A, Kurachi Y Biochem Biophys Res Commun. 2011 Apr 8;407(2):366-71. Epub 2011 Mar 17. PMID:21396912^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.