Potassium channels as multi-ion single-file pores.

Potassium channels as multi-ion single-file pores

A literature review reveals many lines of evidence that both delayed rectifier and inward rectifier potassium channels are multi-ion pores. These include unidirectional flux ratios given by the 2--2.5 power of the electrochemical activity ratio, very steeply voltage-dependent block with monovalent blocking ions, relief of block by permeant ions added to the side opposite from the blocking ion, ...

Energetics of Multi-Ion Conduction Pathways in Potassium Ion Channels

Potassium ion channels form pores in cell membranes, allowing potassium ions through while preventing the passage of sodium ions. Despite numerous high-resolution structures, it is not yet possible to relate their structure to their single molecule function other than at a qualitative level. Over the past decade, there has been a concerted effort using molecular dynamics to capture the thermody...

Update on Potassium Ion Channels Potassium Ion Channels: Could They Have Evolved from Viruses?1[W]

Department of Biology, Technische Universität-Darmstadt, Schnittspahnstrasse 3, 64287 Darmstadt, Germany (G.T.); Department of Biosciences, University of Milan, Via Celoria 26, 20133 Milan Italy (A.M.); Information Genomique and Structurale, Unité Mixte de Recherche 7256, Centre National de la Recherche Scientifique, Aix-Marseille Universite, FR–13288 Marseille, France (G.B.); and Department of...

G protein regulation of potassium ion channels.

Multi-ion versus single-ion conduction mechanisms can yield current rectification in biological ion channels.

There is clear evidence that the net magnitude of negative charge at the intracellular end of inwardly rectifying potassium channels helps to generate an asymmetry in the magnitude of the current that will pass in each direction. However, a complete understanding of the physical mechanism that links these charges to current rectification has yet to be obtained. Using Brownian dynamics, we compa...