3jyc
From Proteopedia
Crystal structure of the eukaryotic strong inward-rectifier K+ channel Kir2.2 at 3.1 Angstrom resolution
Structural highlights
FunctionKCJ12_CHICK Inward rectifying potassium channel that is activated by phosphatidylinositol 4,5-bisphosphate and that probably participates in controlling the resting membrane potential in electrically excitable cells. Inward rectifier potassium channels are characterized by a greater tendency to allow potassium to flow into the cell rather than out of it. The inward rectification is probably due to the blockage of outward current by cytoplasmic polyamines and/or magnesium ions.[1] [2] 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 PubMedInward-rectifier potassium (K+) channels conduct K+ ions most efficiently in one direction, into the cell. Kir2 channels control the resting membrane voltage in many electrically excitable cells, and heritable mutations cause periodic paralysis and cardiac arrhythmia. We present the crystal structure of Kir2.2 from chicken, which, excluding the unstructured amino and carboxyl termini, is 90% identical to human Kir2.2. Crystals containing rubidium (Rb+), strontium (Sr2+), and europium (Eu3+) reveal binding sites along the ion conduction pathway that are both conductive and inhibitory. The sites correlate with extensive electrophysiological data and provide a structural basis for understanding rectification. The channel's extracellular surface, with large structured turrets and an unusual selectivity filter entryway, might explain the relative insensitivity of eukaryotic inward rectifiers to toxins. These same surface features also suggest a possible approach to the development of inhibitory agents specific to each member of the inward-rectifier K+ channel family. Crystal structure of the eukaryotic strong inward-rectifier K+ channel Kir2.2 at 3.1 A resolution.,Tao X, Avalos JL, Chen J, MacKinnon R Science. 2009 Dec 18;326(5960):1668-74. PMID:20019282[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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