2qts
Structure of an acid-sensing ion channel 1 at 1.9 A resolution and low pH
Structural highlights
FunctionASIC1_CHICK Cation channel with high affinity for sodium, which is gated by extracellular protons and inhibited by the diuretic amiloride (By similarity).[1] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedAcid-sensing ion channels (ASICs) are voltage-independent, proton-activated receptors that belong to the epithelial sodium channel/degenerin family of ion channels and are implicated in perception of pain, ischaemic stroke, mechanosensation, learning and memory. Here we report the low-pH crystal structure of a chicken ASIC1 deletion mutant at 1.9 A resolution. Each subunit of the chalice-shaped homotrimer is composed of short amino and carboxy termini, two transmembrane helices, a bound chloride ion and a disulphide-rich, multidomain extracellular region enriched in acidic residues and carboxyl-carboxylate pairs within 3 A, suggesting that at least one carboxyl group bears a proton. Electrophysiological studies on aspartate-to-asparagine mutants confirm that these carboxyl-carboxylate pairs participate in proton sensing. Between the acidic residues and the transmembrane pore lies a disulphide-rich 'thumb' domain poised to couple the binding of protons to the opening of the ion channel, thus demonstrating that proton activation involves long-range conformational changes. Structure of acid-sensing ion channel 1 at 1.9 A resolution and low pH.,Jasti J, Furukawa H, Gonzales EB, Gouaux E Nature. 2007 Sep 20;449(7160):316-23. PMID:17882215[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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