See potassium run

@article{Miller2001SeePR,
  title={See potassium run},
  author={Christopher Miller},
  journal={Nature},
  year={2001},
  volume={414},
  pages={23-24}
}
Nearly all cells have membranes spanned by potassium-conducting channel proteins, without which your nerves (and much else) simply wouldn't work. Ion permeation through these channels can now be seen in dazzling detail. 

Ion permeation in potassium ion channels

  • L. Coates
  • Biology
    Acta crystallographica. Section D, Structural biology
  • 2020
Key structural biology experiments that have sought to elucidate how potassium ions permeate and pass through the selectivity filter of potassium ion channels are reviewed.

Pore dimensions and the role of occupancy in unitary conductance of Shaker K channels

The resistance of the inner vestibule limits Shaker’s conductance.

Architecture of a membrane protein: The voltage-gated K + channel

TLDR
Basic channel properties: activation, inactivation and ionic selectivity are discussed in the light of X -ray crystal struct ures of bacterial Kv channels, and a body of work combining mutagenesis with ele c-tro physiology and spectro scopy.

How far can a sodium ion travel within a lipid bilayer?

TLDR
Analogues of a synthetic ion channel made from a helical peptide were used to study the mechanism of cation translocation within bilayer membranes and showed the maximum distance a sodium ion is permitted to travel between two binding sites within a lipid bilayer environment.

Structure–Function Relationships in Ca2+ Cycling Proteins

TLDR
Abstract D. H. Maclennan, M. Abu-Abed and Chulhee Kang investigate the structure and function relationships in Ca2+ Cycling Proteins and the role of EMT in these relationships.

Ion conduction and selectivity in K(+) channels.

  • B. Roux
  • Biology
    Annual review of biophysics and biomolecular structure
  • 2005
TLDR
The purpose of this review is to summarize the most important findings from experiments and computations and to highlight a number of fundamental mechanistic questions about ion conduction and selectivity that will require further work.

Pore size matters for potassium channel conductance

TLDR
The idea that the physical dimensions of the hydrophobic internal vestibule limit ion transport in K+ channels, accounting for their diversity in unitary conductance is raised.

Filter gate closure inhibits ion but not water transport through potassium channels

TLDR
It is shown that K+ channels remain permeable to water, even after entering such an electrically silent conformation, and questions the widely accepted hypothesis that multiple K+ ions in the selectivity filter act to mutually destabilize binding.

Selectivity of the KcsA potassium channel: Analysis and computation.

TLDR
An analytical and computational study of a mathematical model of the KcsA potassium channel, including the effects of ion size (Bikerman model) and solvation energy (Born model), and a hybrid analytical-numerical method to solve the modified PNP system.

K(+) channels: function-structural overview.

TLDR
The present overview discusses in the function, localization, and the relations between function and structure of the five different subfamilies of K(+) channels: (a) inward rectifiers, Kir; (b) four transmembrane segments-2 pores, K2P; (c) voltage-gated, Kv; (d) the Slo family; and (e) Ca(2+)-activated SK family, SKCa.
...

References

SHOWING 1-10 OF 13 REFERENCES

The potassium permeability of a giant nerve fibre

TLDR
This hypothesis is attractive in that it provides a reasonable explanation of the further observation that the sodium efflux drops by some 20 pmole/cm2 sec when external potassium is removed, but it raises one serious difficulty which needs to be resolved.

Energetics of ion conduction through the K+ channel

TLDR
It is found that ion conduction involves transitions between two main states, with two and three K+ ions occupying the selectivity filter, respectively; this process is reminiscent of the ‘knock-on’ mechanism proposed by Hodgkin and Keynes in 1955.

KcsA: it's a potassium channel.

TLDR
Variation of conductance with concentration under symmetrical salt conditions is complex, with at least two ion-binding processes revealing themselves: a high affinity process below 20 mM and a low affinity process over the range 100-1,000 mM.

Ion Channels in Excitable Membranes

TLDR
The action potential is triggered when the membrane potential, which was at the resting level, depolarizes and reaches the threshold of excitation, which triggers the action potential.

Discrete Ba2+ block as a probe of ion occupancy and pore structure in the high-conductance Ca2+ -activated K+ channel

TLDR
The results taken together argue strongly that this channel's conduction pathway contains four sites of very high affinity for K+, all of which may be simultaneously occupied under normal conducting conditions and leads to the unusually high conductance of this K+-specific channel.

The Barium Site in a Potassium Channel by X-Ray Crystallography

TLDR
Structural and functional data imply that at physiological ion concentrations a third ion may interact with two ions in the selectivity filter, perhaps by entering from one side and displacing an ion on the opposite side.

Chemistry of ion coordination and hydration revealed by a K+ channel–Fab complex at 2.0 Å resolution

TLDR
Here it is shown how the K+ channel displaces water molecules around an ion at its extracellular entryway, and how it holds a K+ ion in a square antiprism of water molecules in a cavity near its intracellular entry way.

Energetic optimization of ion conduction rate by the K+ selectivity filter

TLDR
How nearly diffusion-limited rates are achieved, by analysing ion conduction and the corresponding crystallographic ion distribution in the selectivity filter of the KcsA K+ channel, is shown.

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.

Physiol

  • Physiol
  • 1988