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J Physiol
2003 Nov 15;553Pt 1:101-12. doi: 10.1113/jphysiol.2003.052845.
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The effects of spermine on the accessibility of residues in the M2 segment of Kir2.1 channels expressed in Xenopus oocytes.
Chang HK
,
Yeh SH
,
Shieh RC
.
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We examined the effects of spermine binding to aspartate at site 172 on the accessibility of internal trimethylammonioethylmethane thiosulphonate (MTSET) to substituted cysteines within the pore of a Kir2.1 channel. Spermine prevented MTSET modification in Q164C and G168C mutants, indicating that sites 164 and 168 are located externally to the spermine binding site. The rates of MTSET modification were significantly reduced by spermine in I176C mutants, indicating that site 176 is located internally to D172 and that the bound spermine hinders the reaction of MTSET with cysteine at site 176. Spermidine, putrescine and Mg2+ also decreased MTSET modification at site 176. The order of effect is putrescine > spermidine approximately = spermine approximately = Mg2+. To account for the electrostatic and physical repulsion between MTSET and polyamines, possible locations of polyamines in the pore are discussed. In D172C mutants, the spermine that bound to sites 224 and 299 completely inhibited channels at +40 mV, yet MTSET remained accessible to site 172. In addition, in the D172C mutant, spermine did not affect the exit rate of Ba2+ bound to the threonine at the site 141. These results indicate that spermine bound at the cytoplasmic pore induces channel closure at positions 141-172. The effects of spermine on the accessibility of amino acids in the pore may shed light on the structural and functional relationships of the Kir2.1 channels during inward rectification.
Alagem,
Mechanism of Ba(2+) block of a mouse inwardly rectifying K+ channel: differential contribution by two discrete residues.
2001, Pubmed,
Xenbase
Alagem,
Mechanism of Ba(2+) block of a mouse inwardly rectifying K+ channel: differential contribution by two discrete residues.
2001,
Pubmed
,
Xenbase
Choe,
Three distinct structural environments of a transmembrane domain in the inwardly rectifying potassium channel ROMK1 defined by perturbation.
1995,
Pubmed
,
Xenbase
Collins,
Scanning mutagenesis of the putative transmembrane segments of Kir2.1, an inward rectifier potassium channel.
1997,
Pubmed
,
Xenbase
Fujiwara,
Ser165 in the second transmembrane region of the Kir2.1 channel determines its susceptibility to blockade by intracellular Mg2+.
2002,
Pubmed
,
Xenbase
Hamill,
Improved patch-clamp techniques for high-resolution current recording from cells and cell-free membrane patches.
1981,
Pubmed
Huang,
Direct activation of inward rectifier potassium channels by PIP2 and its stabilization by Gbetagamma.
1998,
Pubmed
,
Xenbase
Jiang,
Crystal structure and mechanism of a calcium-gated potassium channel.
2002,
Pubmed
Jiang,
The barium site in a potassium channel by x-ray crystallography.
2000,
Pubmed
Kubo,
Control of rectification and permeation by two distinct sites after the second transmembrane region in Kir2.1 K+ channel.
2001,
Pubmed
,
Xenbase
Kubo,
Primary structure and functional expression of a mouse inward rectifier potassium channel.
1993,
Pubmed
,
Xenbase
Kuo,
Crystal structure of the potassium channel KirBac1.1 in the closed state.
2003,
Pubmed
Lopatin,
Potassium channel block by cytoplasmic polyamines as the mechanism of intrinsic rectification.
1994,
Pubmed
,
Xenbase
Lopatin,
The mechanism of inward rectification of potassium channels: "long-pore plugging" by cytoplasmic polyamines.
1995,
Pubmed
,
Xenbase
Loussouarn,
Structure and dynamics of the pore of inwardly rectifying K(ATP) channels.
2000,
Pubmed
Lu,
Architecture of a K+ channel inner pore revealed by stoichiometric covalent modification.
1999,
Pubmed
,
Xenbase
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
Minor,
Transmembrane structure of an inwardly rectifying potassium channel.
1999,
Pubmed
Nishida,
Structural basis of inward rectification: cytoplasmic pore of the G protein-gated inward rectifier GIRK1 at 1.8 A resolution.
2002,
Pubmed
Shieh,
Interaction of Ba2+ with the pores of the cloned inward rectifier K+ channels Kir2.1 expressed in Xenopus oocytes.
1998,
Pubmed
,
Xenbase
Stanfield,
A single aspartate residue is involved in both intrinsic gating and blockage by Mg2+ of the inward rectifier, IRK1.
1994,
Pubmed
Taglialatela,
C-terminus determinants for Mg2+ and polyamine block of the inward rectifier K+ channel IRK1.
1995,
Pubmed
,
Xenbase
Thompson,
Residues beyond the selectivity filter of the K+ channel kir2.1 regulate permeation and block by external Rb+ and Cs+.
2000,
Pubmed
Vandenberg,
Inward rectification of a potassium channel in cardiac ventricular cells depends on internal magnesium ions.
1987,
Pubmed
Wible,
Gating of inwardly rectifying K+ channels localized to a single negatively charged residue.
1994,
Pubmed
,
Xenbase
Xie,
Spermine block of the strong inward rectifier potassium channel Kir2.1: dual roles of surface charge screening and pore block.
2002,
Pubmed
,
Xenbase
Yang,
Control of rectification and permeation by residues in two distinct domains in an inward rectifier K+ channel.
1995,
Pubmed
,
Xenbase
