Crystal structure and mechanism of a calcium-gated potassium channel

@article{Jiang2002CrystalSA,
  title={Crystal structure and mechanism of a calcium-gated potassium channel},
  author={Youxing Jiang and Alice Lee and Jiayun Chen and Martine Cadene and Brian T. Chait and Roderick MacKinnon},
  journal={Nature},
  year={2002},
  volume={417},
  pages={515-522}
}
Ion channels exhibit two essential biophysical properties; that is, selective ion conduction, and the ability to gate-open in response to an appropriate stimulus. Two general categories of ion channel gating are defined by the initiating stimulus: ligand binding (neurotransmitter- or second-messenger-gated channels) or membrane voltage (voltage-gated channels). Here we present the structural basis of ligand gating in a K+ channel that opens in response to intracellular Ca2+. We have cloned… 

Crystal Structure of a Mammalian Voltage-Dependent Shaker Family K+ Channel

TLDR
Electrostatic properties of the side portals and positions of the T1 domain and β sub unit are consistent with electrophysiological studies of inactivation gating and with the possibility of K+ channel regulation by the β subunit.

Voltage-Gated Potassium Channels: A Structural Examination of Selectivity and Gating.

TLDR
The remarkable features of voltage-gated potassium channels are illustrated and the mechanisms used by these machines are explained with experimental data.

Structure of the Human BK Ion Channel in Lipid Environment

TLDR
The random spherically constrained (RSC) single-particle cryo-EM method was employed to study human large conductance voltage- and calcium-activated potassium channels reconstituted into liposomes and found a twofold symmetry in hBK in liposome.

Structure of the Human BK Channel Ca2+-Activation Apparatus at 3.0 Å Resolution

TLDR
The structure suggests that the Ca2+ gating ring, in addition to regulating the pore directly, may also modulate the voltage sensor and therefore play a central role in numerous physiological processes.

X-ray structure of a voltage-dependent K+ channel

TLDR
The structure of KvAP, a voltage-dependent K+ channel from Aeropyrum pernix, is presented and a crystal structure of the full-length channel at a resolution of 3.2 Å is determined, which suggests that the voltage-sensor paddles move in response to membrane voltage changes, carrying their positive charge across the membrane.

Localization of the Activation Gate of a Voltage-gated Ca2+ Channel

TLDR
The results suggest that the S6 helices of the α1 subunit of VGCCs undergo conformation changes during gating and the activation gate is located at the intracellular end of the pore.

Conformational dynamics of the KcsA potassium channel governs gating properties

TLDR
NMR studies of full-length KcsA, a prototypical K+ channel, in its open, closed and intermediate states reveal that at least two conformational states exist both in the selectivity filter and near the C-terminal ends of the TM2 helices.

How does voltage open an ion channel?

TLDR
This review focuses on the molecular mechanisms by which voltage-gated ion channels convert changes in membrane voltage into the opening and closing of "gates" that turn ion conductance on and off.

Broken symmetry in the human BK channel

TLDR
The RSC single-particle cryo-EM method was employed to study the human large conductance voltage- and calcium-activated potassium (hBK or hSlo1) channels reconstituted into liposomes and found a two-fold symmetry was observed in hBK.
...

References

SHOWING 1-10 OF 46 REFERENCES

Mechanism of calcium gating in small-conductance calcium-activated potassium channels

TLDR
The mechanism of calcium gating is studied and it is found that small-conductance calcium-activated potassium channels are not gated by calcium binding directly to the channel α-subunits, instead, the functional SK channels are heteromeric complexes with calmodulin, which is constitutively associated with the α- subunits in a calcium-independent manner.

The open pore conformation of potassium channels

TLDR
Amino-acid sequence conservation suggests a common structural basis for gating in a wide range of K+ channels, both ligand- and voltage-gated.

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

TLDR
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.

Voltage gating of ion channels

TLDR
Voltage-gated sodium channels initiate the nerve action potential and provide for its rapid propagation because the ion fluxes through these channels regeneratively cause more channels to open.

Gating kinetics of Ca2+-activated K+ channels from rat muscle incorporated into planar lipid bilayers. Evidence for two voltage- dependent Ca2+ binding reactions

TLDR
The results provide evidence for a novel regulatory mechanism for the activity of an ion channel: modulation by voltage of the binding of an agonist molecule, in this case, Ca2+ ion.

Allosteric effects of Mg2+ on the gating of Ca2+-activated K+ channels from mammalian skeletal muscle.

TLDR
The results argue that this high-conductance, Ca2+-activated K+ channel contains at least six Ca2-binding sites involved in the activation process.

Cyclic nucleotide-gated ion channels: an extended family with diverse functions.

TLDR
An ion channel directly activated by cGMP was first discovered about ten years ago and both channel classes are reviewed here, covering the cyclic-nucleotide binding site on these channels, ion permeation, pharmacological blockers, channel gating and modulation, and physiological functions of the channels.

Separation of Gating Properties from Permeation and Block in mslo Large Conductance Ca-activated K+ Channels

TLDR
The kinetic and steady-state properties of macroscopic mslo Ca-activated K+ currents are examined in order to interpret these currents in terms of the gating behavior of the mslo channel and it is found that the maximum open probability of the MSlo channel is the same or very similar over a Ca2+ concentration range spanning three orders of magnitude indicating that over this range the internal Ca2- concentration does not limit the ability of the channel to be activated by voltage.