Atomic scale movement of the voltage-sensing region in a potassium channel measured via spectroscopy

  title={Atomic scale movement of the voltage-sensing region in a potassium channel measured via spectroscopy},
  author={Albert Cha and Gregory E. Snyder and Paul R. Selvin and Francisco Bezanilla},
Voltage-gated ion channels are transmembrane proteins that are essential for nerve impulses and regulate ion flow across cell membranes in response to changes in membrane potential. They are made up of four homologous domains or subunits, each of which contains six transmembrane segments. Studies of potassium channels have shown that the second (S2) and fourth (S4) segments contain several charged residues, which sense changes in voltage and form part of the voltage sensor. Although these… 

Small vertical movement of a K+ channel voltage sensor measured with luminescence energy transfer

This small movement of the voltage-sensor segments in functional Shaker K+ channels supports an alternative model in which the protein shapes the electric field profile, focusing it across a narrow region of S4 (ref. 6).

Ion Channel Voltage Sensors: Structure, Function, and Pathophysiology

Gating charge displacement in voltage-gated ion channels involves limited transmembrane movement

A molecular model of voltage gating is proposed that can account for the observed 13e gating charge with limited transmembrane S4 movement and indicates that the S4 segment does not translocate across the lipid bilayer.

Structural mechanism of voltage-dependent gating in an isolated voltage-sensing domain

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Structural basis for gating charge movement in the voltage sensor of a sodium channel

High-resolution structural models of resting, intermediate, and activated states of the voltage-sensing domain of the bacterial sodium channel NaChBac are constructed using the Rosetta modeling method, crystal structures of related channels, and experimental data showing state-dependent interactions between the gating charge-carrying arginines in the S4 segment and negatively charged residues in neighboring transmembrane segments.

Constraints on Voltage Sensor Movement in the Shaker K+ Channel

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Functional diversity of potassium channel voltage-sensing domains

Differences in detailed VSD functioning among voltage-gated potassium channels might have physiological consequences that have not been explored and which might reflect evolutionary adaptations to the different roles played by Kv channels in cell physiology.

Molecular mechanism of voltage sensor movements in a potassium channel

This work investigated how S4 moves relative to the pore domain in the prototypical Shaker potassium channel and suggested a novel mechanism: in the resting state, the top of the S3b–S4 voltage sensor paddle lies close to thetop of S5 of the adjacent subunit, but moves towards the topOf its own subunit during depolarization.

Characterization of cardiac IKs channel gating using voltage clamp fluorometry

This thesis work focuses on elucidating the mechanisms underlying the voltage-dependent gating of a member of the voltage gated potassium (Kv) channel family, KCNQ1, where it comprises the alpha subunit of the slowly activating delayed rectifier current, IKs.



Spectroscopic mapping of voltage sensor movement in the Shaker potassium channel

It is proposed that helical twist contributes to the movement of charged side chains across the membrane electric field and that it is involved in coupling voltage sensing to gating.

The voltage sensor in voltage-dependent ion channels.

The theoretical basis of the energy coupling between the electric field and the voltage is presented, which allows the interpretation of the gating charge that moves in one channel, and the novel results on lanthanide-based resonance energy transfer that show small distance changes between residues in the channel molecule.

Atomic scale structure and functional models of voltage-gated potassium channels.

Direct Physical Measure of Conformational Rearrangement Underlying Potassium Channel Gating

During channel activation, a stretch of at least seven amino acids of the putative transmembrane segment S4 moved from a buried position into the extracellular environment, providing physical evidence in support of the hypothesis that S4 is the voltage sensor of voltage-gated ion channels.

Currents Related to Movement of the Gating Particles of the Sodium Channels

By use of signal averaging techniques, small transient currents are observed which are believed to be the gating currents of the sodium channels.

Activation of Shaker Potassium Channels I. Characterization of Voltage-dependent Transitions

The conformational changes associated with activation gating in Shaker potassium channels are functionally characterized in patch-clamp recordings made from Xenopus laevis oocytes expressing Shaker channels with fast inactivation removed, forming the basis for constraining a detailed gating model to be described in a subsequent paper of this series.

The structure of the potassium channel: molecular basis of K+ conduction and selectivity.

The architecture of the pore establishes the physical principles underlying selective K+ conduction, which promotes ion conduction by exploiting electrostatic repulsive forces to overcome attractive forces between K+ ions and the selectivity filter.