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.
Biophys J
2004 Nov 01;875:3110-21. doi: 10.1529/biophysj.104.044602.
Show Gene links
Show Anatomy links
Binding site in eag voltage sensor accommodates a variety of ions and is accessible in closed channel.
Silverman WR
,
Bannister JP
,
Papazian DM
.
???displayArticle.abstract???
In ether-a-go-go K+ channels, voltage-dependent activation is modulated by ion binding to a site located in an extracellular-facing crevice between transmembrane segments S2 and S3 in the voltage sensor. We find that acidic residues D278 in S2 and D327 in S3 are able to coordinate a variety of divalent cations, including Mg2+, Mn2+, and Ni2+, which have qualitatively similar functional effects, but different half-maximal effective concentrations. Our data indicate that ions binding to individual voltage sensors in the tetrameric channel act without cooperativity to modulate activation gating. We have taken advantage of the unique phenotype of Ni2+ in the D274A channel, which contains a mutation of a nonbinding site residue, to demonstrate that ions can access the binding site from the extracellular solution when the voltage sensor is in the resting conformation. Our results are difficult to reconcile with the x-ray structure of the KvAP K+ channel, in which the binding site residues are widely separated, and with the hydrophobic paddle model for voltage-dependent activation, in which the voltage sensor domain, including the S3-S4 loop, is near the cytoplasmic side of the membrane in the closed channel.
Andersson,
Structural basis for the negative allostery between Ca(2+)- and Mg(2+)-binding in the intracellular Ca(2+)-receptor calbindin D9k.
1997, Pubmed
Andersson,
Structural basis for the negative allostery between Ca(2+)- and Mg(2+)-binding in the intracellular Ca(2+)-receptor calbindin D9k.
1997,
Pubmed
Bezanilla,
Inactivation of the sodium channel. I. Sodium current experiments.
1977,
Pubmed
Dudev,
Principles governing Mg, Ca, and Zn binding and selectivity in proteins.
2003,
Pubmed
Goldgur,
Structure of the HIV-1 integrase catalytic domain complexed with an inhibitor: a platform for antiviral drug design.
1999,
Pubmed
Harutyunyan,
Crystal structure of holo inorganic pyrophosphatase from Escherichia coli at 1.9 A resolution. Mechanism of hydrolysis.
1997,
Pubmed
Jiang,
X-ray structure of a voltage-dependent K+ channel.
2003,
Pubmed
Jiang,
The principle of gating charge movement in a voltage-dependent K+ channel.
2003,
Pubmed
Kankare,
Crystallographic identification of metal-binding sites in Escherichia coli inorganic pyrophosphatase.
1996,
Pubmed
Lainé,
Atomic proximity between S4 segment and pore domain in Shaker potassium channels.
2003,
Pubmed
,
Xenbase
Landt,
A general method for rapid site-directed mutagenesis using the polymerase chain reaction.
1990,
Pubmed
Larsen,
Ligand-induced domain movement in pyruvate kinase: structure of the enzyme from rabbit muscle with Mg2+, K+, and L-phospholactate at 2.7 A resolution.
1997,
Pubmed
Nichols,
Structure and function of an archaeal topoisomerase VI subunit with homology to the meiotic recombination factor Spo11.
1999,
Pubmed
Papazian,
Alteration of voltage-dependence of Shaker potassium channel by mutations in the S4 sequence.
1991,
Pubmed
,
Xenbase
Sarkar,
The "megaprimer" method of site-directed mutagenesis.
1990,
Pubmed
Schönherr,
Individual subunits contribute independently to slow gating of bovine EAG potassium channels.
1999,
Pubmed
Schönherr,
Conformational switch between slow and fast gating modes: allosteric regulation of voltage sensor mobility in the EAG K+ channel.
2002,
Pubmed
,
Xenbase
Silverman,
Mg(2+) modulates voltage-dependent activation in ether-à-go-go potassium channels by binding between transmembrane segments S2 and S3.
2000,
Pubmed
,
Xenbase
Silverman,
Structural basis of two-stage voltage-dependent activation in K+ channels.
2003,
Pubmed
,
Xenbase
Sliz,
The structure of enzyme IIAlactose from Lactococcus lactis reveals a new fold and points to possible interactions of a multicomponent system.
1997,
Pubmed
Stec,
Kinetic and X-ray structural studies of three mutant E. coli alkaline phosphatases: insights into the catalytic mechanism without the nucleophile Ser102.
1998,
Pubmed
Tang,
Extracellular Mg(2+) modulates slow gating transitions and the opening of Drosophila ether-à-Go-Go potassium channels.
2000,
Pubmed
,
Xenbase
Tang,
Transfer of voltage independence from a rat olfactory channel to the Drosophila ether-à-go-go K+ channel.
1997,
Pubmed
Terlau,
Extracellular Mg2+ regulates activation of rat eag potassium channel.
1996,
Pubmed
,
Xenbase
Timpe,
Expression of functional potassium channels from Shaker cDNA in Xenopus oocytes.
1988,
Pubmed
,
Xenbase
Tiwari-Woodruff,
Voltage-dependent structural interactions in the Shaker K(+) channel.
2000,
Pubmed
,
Xenbase
Warmke,
A family of potassium channel genes related to eag in Drosophila and mammals.
1994,
Pubmed
