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Hydrophobic mutations alter the movement of Mg2+ in the pore of voltage-gated potassium channels.
Harris RE, Isacoff EY.
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The permeation pathways of the voltage-gated K+ channels Kv3.1 and ShakerB delta 6-46 (ShB delta) were studied using Mg2+ block. Internal Mg2+ blocked both channels in a voltage-dependent manner, and block was partially relieved by external K+, consistent with Mg2+ binding within the pore. The kinetics of Mg2+ block was much faster for Kv3.1 than for ShB delta. Fast block of Kv3.1 was transferred to ShB delta with transplantation of the P-region, but not of S6. The difference in the P-region, causing the change in Mg2+ binding kinetics, was attributed to ShB delta (V443) and its analog Kv3.1(L401), because in both channels leucine at this position gave fast block, whereas valine gave slow block. For Kv3.1 the major determinant of the voltage dependence of Mg2+ binding resided primarily in the off rate, whereas for Kv3.1(L401V) the voltage dependence resided primarily in the on rate, consistent with a change in the rate-limiting barrier for Mg2+ binding. Our data suggest that hydrophobic residues at positions 401 of Kv3.1 and 443 of ShB delta act as barriers to the movement of Mg2+ in the pore.
Aiyar,
The P-region and S6 of Kv3.1 contribute to the formation of the ion conduction pathway.
1994, Pubmed,
Xenbase
Aiyar,
The P-region and S6 of Kv3.1 contribute to the formation of the ion conduction pathway.
1994,
Pubmed
,
Xenbase Aiyar,
Topology of the pore-region of a K+ channel revealed by the NMR-derived structures of scorpion toxins.
1995,
Pubmed Armstrong,
Block of squid axon K channels by internally and externally applied barium ions.
1982,
Pubmed Brocard,
Glutamate-induced increases in intracellular free Mg2+ in cultured cortical neurons.
1993,
Pubmed Choi,
The internal quaternary ammonium receptor site of Shaker potassium channels.
1993,
Pubmed
,
Xenbase Goldstein,
The charybdotoxin receptor of a Shaker K+ channel: peptide and channel residues mediating molecular recognition.
1994,
Pubmed
,
Xenbase Heginbotham,
A functional connection between the pores of distantly related ion channels as revealed by mutant K+ channels.
1992,
Pubmed
,
Xenbase Heginbotham,
The aromatic binding site for tetraethylammonium ion on potassium channels.
1992,
Pubmed Heginbotham,
Mutations in the K+ channel signature sequence.
1994,
Pubmed
,
Xenbase Hidalgo,
Revealing the architecture of a K+ channel pore through mutant cycles with a peptide inhibitor.
1995,
Pubmed
,
Xenbase HODGKIN,
The potassium permeability of a giant nerve fibre.
1955,
Pubmed Hoshi,
Biophysical and molecular mechanisms of Shaker potassium channel inactivation.
1990,
Pubmed
,
Xenbase Isacoff,
Putative receptor for the cytoplasmic inactivation gate in the Shaker K+ channel.
1991,
Pubmed
,
Xenbase Kubo,
Primary structure and functional expression of a mouse inward rectifier potassium channel.
1993,
Pubmed
,
Xenbase Kürz,
Side-chain accessibilities in the pore of a K+ channel probed by sulfhydryl-specific reagents after cysteine-scanning mutagenesis.
1995,
Pubmed
,
Xenbase Lopatin,
Potassium channel block by cytoplasmic polyamines as the mechanism of intrinsic rectification.
1994,
Pubmed
,
Xenbase Lopez,
Evidence that the S6 segment of the Shaker voltage-gated K+ channel comprises part of the pore.
1994,
Pubmed
,
Xenbase Lu,
Probing a potassium channel pore with an engineered protonatable site.
1995,
Pubmed
,
Xenbase Lu,
Electrostatic tuning of Mg2+ affinity in an inward-rectifier K+ channel.
1994,
Pubmed
,
Xenbase Lü,
Silver as a probe of pore-forming residues in a potassium channel.
1995,
Pubmed
,
Xenbase Ludewig,
A site accessible to extracellular TEA+ and K+ influences intracellular Mg2+ block of cloned potassium channels.
1993,
Pubmed MacKinnon,
Mutant potassium channels with altered binding of charybdotoxin, a pore-blocking peptide inhibitor.
1989,
Pubmed
,
Xenbase MacKinnon,
Mapping the receptor site for charybdotoxin, a pore-blocking potassium channel inhibitor.
1990,
Pubmed
,
Xenbase MacKinnon,
Mutations affecting TEA blockade and ion permeation in voltage-activated K+ channels.
1990,
Pubmed Matsuda,
Effects of external and internal K+ ions on magnesium block of inwardly rectifying K+ channels in guinea-pig heart cells.
1991,
Pubmed Matsuda,
Ohmic conductance through the inwardly rectifying K channel and blocking by internal Mg2+.
,
Pubmed Neyton,
Potassium blocks barium permeation through a calcium-activated potassium channel.
1988,
Pubmed Neyton,
Discrete Ba2+ block as a probe of ion occupancy and pore structure in the high-conductance Ca2+ -activated K+ channel.
1988,
Pubmed Pascual,
K+ pore structure revealed by reporter cysteines at inner and outer surfaces.
1995,
Pubmed
,
Xenbase Slesinger,
The S4-S5 loop contributes to the ion-selective pore of potassium channels.
1993,
Pubmed
,
Xenbase Taglialatela,
Regulation of K+/Rb+ selectivity and internal TEA blockade by mutations at a single site in K+ pores.
1993,
Pubmed Taglialatela,
Specification of pore properties by the carboxyl terminus of inwardly rectifying K+ channels.
1994,
Pubmed
,
Xenbase Taglialatela,
Comparison of H5, S6, and H5-S6 exchanges on pore properties of voltage-dependent K+ channels.
1994,
Pubmed
,
Xenbase Wible,
Gating of inwardly rectifying K+ channels localized to a single negatively charged residue.
1994,
Pubmed
,
Xenbase Woodhull,
Ionic blockage of sodium channels in nerve.
1973,
Pubmed Yang,
Control of rectification and permeation by residues in two distinct domains in an inward rectifier K+ channel.
1995,
Pubmed
,
Xenbase Yellen,
Relief of Na+ block of Ca2+-activated K+ channels by external cations.
1984,
Pubmed Yellen,
Ionic permeation and blockade in Ca2+-activated K+ channels of bovine chromaffin cells.
1984,
Pubmed Yellen,
Mutations affecting internal TEA blockade identify the probable pore-forming region of a K+ channel.
1991,
Pubmed Yool,
Alteration of ionic selectivity of a K+ channel by mutation of the H5 region.
1991,
Pubmed
,
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