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Proc Natl Acad Sci U S A
2007 May 08;10419:7904-9. doi: 10.1073/pnas.0702638104.
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Two atomic constraints unambiguously position the S4 segment relative to S1 and S2 segments in the closed state of Shaker K channel.
Campos FV, Chanda B, Roux B, Bezanilla F.
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It is now well established that the voltage-sensing S4 segment in voltage-dependent ion channels undergoes a conformational change in response to varying membrane potential. However, the magnitude of the movement of S4 relative to the membrane and the rest of the protein remains controversial. Here, by using histidine scanning mutagenesis in the Shaker K channel, we identified mutants I241H (S1 segment) and I287H (S2 segment) that generate inward currents at hyperpolarized potentials, suggesting that these residues are part of a hydrophobic plug that separates the water-accessible crevices. Additional experiments with substituted cysteine residues showed that, at hyperpolarized potentials, both I241C and I287C can spontaneously form disulphide and metal bridges with R362C, the position of the first charge-carrying residue in S4. These results constrain unambiguously the closed-state positions of the S4 segment with respect to the S1 and S2 segments, which are known to undergo little or no movement during gating. To satisfy these constraints, the S4 segment must undergo an axial rotation of approximately 180 degrees and a transmembrane (vertical) movement of approximately 6.5 A at the level of R362 in going from the open to the closed state of the channel, moving the gating charge across a focused electric field.
Aggarwal,
Contribution of the S4 segment to gating charge in the Shaker K+ channel.
1996, Pubmed,
Xenbase
Aggarwal,
Contribution of the S4 segment to gating charge in the Shaker K+ channel.
1996,
Pubmed
,
Xenbase Ahern,
Focused electric field across the voltage sensor of potassium channels.
2005,
Pubmed
,
Xenbase Asamoah,
A fluorometric approach to local electric field measurements in a voltage-gated ion channel.
2003,
Pubmed Baker,
Three transmembrane conformations and sequence-dependent displacement of the S4 domain in shaker K+ channel gating.
1998,
Pubmed Careaga,
Thermal motions of surface alpha-helices in the D-galactose chemosensory receptor. Detection by disulfide trapping.
1992,
Pubmed Cha,
Atomic scale movement of the voltage-sensing region in a potassium channel measured via spectroscopy.
1999,
Pubmed Chanda,
Gating charge displacement in voltage-gated ion channels involves limited transmembrane movement.
2005,
Pubmed del Camino,
Tight steric closure at the intracellular activation gate of a voltage-gated K(+) channel.
2001,
Pubmed Glauner,
Spectroscopic mapping of voltage sensor movement in the Shaker potassium channel.
1999,
Pubmed
,
Xenbase Gonzalez,
S3b amino acid residues do not shuttle across the bilayer in voltage-dependent Shaker K+ channels.
2005,
Pubmed
,
Xenbase Gonzalez,
Periodic perturbations in Shaker K+ channel gating kinetics by deletions in the S3-S4 linker.
2001,
Pubmed
,
Xenbase HODGKIN,
A quantitative description of membrane current and its application to conduction and excitation in nerve.
1952,
Pubmed Holmgren,
The activation gate of a voltage-gated K+ channel can be trapped in the open state by an intersubunit metal bridge.
1998,
Pubmed Hoshi,
Biophysical and molecular mechanisms of Shaker potassium channel inactivation.
1990,
Pubmed
,
Xenbase Jiang,
The principle of gating charge movement in a voltage-dependent K+ channel.
2003,
Pubmed Larsson,
Transmembrane movement of the shaker K+ channel S4.
1996,
Pubmed
,
Xenbase Long,
Crystal structure of a mammalian voltage-dependent Shaker family K+ channel.
2005,
Pubmed Luo,
Kinetics and mechanism of the reaction of cysteine and hydrogen peroxide in aqueous solution.
2005,
Pubmed Olcese,
Correlation between charge movement and ionic current during slow inactivation in Shaker K+ channels.
1997,
Pubmed
,
Xenbase Perozo,
Gating currents from a nonconducting mutant reveal open-closed conformations in Shaker K+ channels.
1993,
Pubmed Posson,
Small vertical movement of a K+ channel voltage sensor measured with luminescence energy transfer.
2005,
Pubmed
,
Xenbase Ruta,
Calibrated measurement of gating-charge arginine displacement in the KvAP voltage-dependent K+ channel.
2005,
Pubmed Schoppa,
The size of gating charge in wild-type and mutant Shaker potassium channels.
1992,
Pubmed Seoh,
Voltage-sensing residues in the S2 and S4 segments of the Shaker K+ channel.
1996,
Pubmed
,
Xenbase Sprunger,
Effects of charybdotoxin on K+ channel (KV1.2) deactivation and inactivation kinetics.
1996,
Pubmed
,
Xenbase Starace,
Histidine scanning mutagenesis of basic residues of the S4 segment of the shaker k+ channel.
2001,
Pubmed
,
Xenbase Starace,
Voltage-dependent proton transport by the voltage sensor of the Shaker K+ channel.
1997,
Pubmed Starace,
A proton pore in a potassium channel voltage sensor reveals a focused electric field.
2004,
Pubmed Stefani,
Cut-open oocyte voltage-clamp technique.
1998,
Pubmed
,
Xenbase Tombola,
Voltage-sensing arginines in a potassium channel permeate and occlude cation-selective pores.
2005,
Pubmed
,
Xenbase Tombola,
The twisted ion-permeation pathway of a resting voltage-sensing domain.
2007,
Pubmed
,
Xenbase Treptow,
Environment of the gating charges in the Kv1.2 Shaker potassium channel.
2006,
Pubmed Webster,
Intracellular gate opening in Shaker K+ channels defined by high-affinity metal bridges.
2004,
Pubmed Yang,
Evidence for voltage-dependent S4 movement in sodium channels.
1995,
Pubmed
