2qks | pdb_00002qks
Crystal structure of a Kir3.1-prokaryotic Kir channel chimera
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Overview
The Kir3.1 K(+) channel participates in heart rate control and neuronal, excitability through G-protein and lipid signaling pathways. Expression in, Escherichia coli has been achieved by replacing three fourths of the, transmembrane pore with the pore of a prokaryotic Kir channel, leaving the, cytoplasmic pore and membrane interfacial regions of Kir3.1 origin. Two, structures were determined at 2.2 A. The selectivity filter is identical, to the Streptomyces lividans K(+) channel within error of measurement, (r.m.s.d.<0.2 A), suggesting that K(+) selectivity requires extreme, conservation of three-dimensional structure. Multiple K(+) ions reside, within the pore and help to explain voltage-dependent Mg(2+) and polyamine, blockade and strong rectification. Two constrictions, at the inner helix, bundle and at the apex of the cytoplasmic pore, may function as gates: in, one structure the apex is open and in the other, it is closed. Gating of, the apex is mediated by rigid-body movements of the cytoplasmic pore, subunits. Phosphatidylinositol 4,5-biphosphate-interacting residues, suggest a possible mechanism by which the signaling lipid regulates the, cytoplasmic pore.
About this Structure
2QKS is a Single protein structure of sequence from Mus musculus, burkholderia xenovornas with BNG and K as ligands. Full crystallographic information is available from OCA.
Reference
Crystal structure of a Kir3.1-prokaryotic Kir channel chimera., Nishida M, Cadene M, Chait BT, Mackinnon R, EMBO J. 2007 Aug 16;. PMID:17703190
Page seeded by OCA on Wed Jan 23 13:32:13 2008
