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PDBsum entry 2wlm
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Metal transport
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PDB id
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2wlm
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References listed in PDB file
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Key reference
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Title
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Domain reorientation and rotation of an intracellular assembly regulate conduction in kir potassium channels.
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Authors
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O.B.Clarke,
A.T.Caputo,
A.P.Hill,
J.I.Vandenberg,
B.J.Smith,
J.M.Gulbis.
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Ref.
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Cell, 2010,
141,
1018-1029.
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PubMed id
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Abstract
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Potassium channels embedded in cell membranes employ gates to regulate K+
current. While a specific constriction in the permeation pathway has
historically been implicated in gating, recent reports suggest that the
signature ion selectivity filter located in the outer membrane leaflet may be
equally important. Inwardly rectifying K+ channels also control the
directionality of flow, using intracellular polyamines to stem ion efflux by a
valve-like action. This study presents crystallographic evidence of
interdependent gates in the conduction pathway and reveals the mechanism of
polyamine block. Reorientation of the intracellular domains, concomitant with
activation, instigates polyamine release from intracellular binding sites to
block the permeation pathway. Conformational adjustments of the slide helices,
achieved by rotation of the cytoplasmic assembly relative to the pore, are
directly correlated to the ion configuration in the selectivity filter. Ion
redistribution occurs irrespective of the constriction, suggesting a more
expansive role of the selectivity filter in gating than previously appreciated.
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