Potassium channels can conduct passively K+ ions with rates of up to approximately 10(8) ions per second at physiological conditions, and they are selective to these species by a factor of 10(4) over Na+ ions. Ion conduction has been proposed to involve transitions between 2 main states, with 2 or 3 K+ ions occupying the selectivity filter separated by an intervening water molecule. The largest free energy barrier of such a process was reported to be of the order of 2-3 kcal mol(-1). Here, we present an alternative mechanism for conduction of K+ in potassium channels where site vacancies are involved, and we propose that coexistence of several ion permeation mechanisms is energetically possible. Conduction can be described as a more anarchic phenomenon than previously characterized by the concerted translocations of K+-water-K+.
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|Titolo:||Atypical mechanism of conduction in potassium channels|
|Citazione:||Furini, S., & Domene, C. (2009). Atypical mechanism of conduction in potassium channels. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 106(38), 16074-16077.|
|Appare nelle tipologie:||1.1 Articolo in rivista|
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