Potassium ions move like Newton's balls

ion conduction mechanism across membranes.

Tudor Toma(t.toma@ic.ac.uk)
Nov 1, 2001

Potassium (K+) channels are essential for the correct functioning of nerves and muscles. But the mechanism by which these tiny protein pores enable the extremely fast transfer of K+, whilst blocking the transfer of smaller ions such as sodium remains unknown. Three papers in 1 November Nature reveal, at the molecular level, how K+ channels proteins work and agree on a mathematical model of K+ flow across the cell membrane.

João Morais-Cabral and colleagues from the laboratory of Roderick MacKinnon at Rockefeller University in New York — that gave us the first atomic-resolution picture of a K+ channel — shows that K+ ions move in a concerted fashion between two configurations, K+-water-K+-water (1,3 configuration) and water-K+-water-K+(2,4 configuration), until a third ion enters, displacing the ion on the opposite side of the queue (Nature...

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