Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
Localization of divalent cation-binding site in the pore of a small conductance Ca(2+)-activated K(+) channel and its role in determining current-voltage relationship.
Soh H
,
Park CS
.
???displayArticle.abstract???
In our previous study, we proposed that the inwardly rectifying current-voltage (I-V) relationship of small-conductance Ca(2+)-activated K(+) channels (SK(Ca) channels) is the result of voltage-dependent blockade of K(+) currents by intracellular divalent cations. We expressed a cloned SK(Ca) channel, rSK2, in Xenopus oocytes and further characterized the nature of the divalent cation-binding site by electrophysiological means. Using site-directed substitution of hydrophilic residues in K(+)-conducting pathway and subsequent functional analysis of mutations, we identified an amino acid residue, Ser-359, in the pore-forming region of rSK2 critical for the strong rectification of the I-V relationship. This residue interacts directly with intracellular divalent cations and determines the ionic selectivity. Therefore, we confirmed our proposition by localizing the divalent cation-binding site within the conduction pathway of the SK(Ca) channel. Because the Ser residue unique for the subfamily of SK(Ca) channels is likely to locate closely to the selectivity filter of the channels, it may also contribute to other permeation characteristics of SK(Ca) channels.
Bond,
Cloning and expression of a family of inward rectifier potassium channels.
1994, Pubmed,
Xenbase
Bond,
Cloning and expression of a family of inward rectifier potassium channels.
1994,
Pubmed
,
Xenbase
Doyle,
The structure of the potassium channel: molecular basis of K+ conduction and selectivity.
1998,
Pubmed
Goldstein,
The charybdotoxin receptor of a Shaker K+ channel: peptide and channel residues mediating molecular recognition.
1994,
Pubmed
,
Xenbase
Hidalgo,
Revealing the architecture of a K+ channel pore through mutant cycles with a peptide inhibitor.
1995,
Pubmed
,
Xenbase
Ho,
Cloning and expression of an inwardly rectifying ATP-regulated potassium channel.
1993,
Pubmed
,
Xenbase
Jiang,
The barium site in a potassium channel by x-ray crystallography.
2000,
Pubmed
Keen,
Domains responsible for constitutive and Ca(2+)-dependent interactions between calmodulin and small conductance Ca(2+)-activated potassium channels.
1999,
Pubmed
,
Xenbase
Köhler,
Small-conductance, calcium-activated potassium channels from mammalian brain.
1996,
Pubmed
,
Xenbase
Kubo,
Primary structure and functional expression of a mouse inward rectifier potassium channel.
1993,
Pubmed
,
Xenbase
LeMasurier,
KcsA: it's a potassium channel.
2001,
Pubmed
Lopatin,
[K+] dependence of polyamine-induced rectification in inward rectifier potassium channels (IRK1, Kir2.1).
1996,
Pubmed
,
Xenbase
Lu,
Ion conduction pore is conserved among potassium channels.
2001,
Pubmed
Lu,
Electrostatic tuning of Mg2+ affinity in an inward-rectifier K+ channel.
1994,
Pubmed
,
Xenbase
Matsuda,
Ohmic conductance through the inwardly rectifying K channel and blocking by internal Mg2+.
,
Pubmed
Ranganathan,
Spatial localization of the K+ channel selectivity filter by mutant cycle-based structure analysis.
1996,
Pubmed
Regehr,
Calcium concentration dynamics produced by synaptic activation of CA1 hippocampal pyramidal cells.
1992,
Pubmed
Schreiber,
Energetics of protein-protein interactions: analysis of the barnase-barstar interface by single mutations and double mutant cycles.
1995,
Pubmed
Shrivastava,
Structure and dynamics of K channel pore-lining helices: a comparative simulation study.
2000,
Pubmed
Soh,
Inwardly rectifying current-voltage relationship of small-conductance Ca2+-activated K+ channels rendered by intracellular divalent cation blockade.
2001,
Pubmed
,
Xenbase
Vandenberg,
Inward rectification of a potassium channel in cardiac ventricular cells depends on internal magnesium ions.
1987,
Pubmed
Vergara,
Calcium-activated potassium channels.
1998,
Pubmed
Wible,
Gating of inwardly rectifying K+ channels localized to a single negatively charged residue.
1994,
Pubmed
,
Xenbase
Williams,
Interactions of polyamines with ion channels.
1997,
Pubmed
Woodhull,
Ionic blockage of sodium channels in nerve.
1973,
Pubmed
Xia,
Mechanism of calcium gating in small-conductance calcium-activated potassium channels.
1998,
Pubmed
,
Xenbase
Zhou,
Potassium channel receptor site for the inactivation gate and quaternary amine inhibitors.
2001,
Pubmed
,
Xenbase
Zhou,
Chemistry of ion coordination and hydration revealed by a K+ channel-Fab complex at 2.0 A resolution.
2001,
Pubmed
