Paper Citing NAMD - Abstract
Furini, Simone; Domene, Carmen
Atypical mechanism of conduction in potassium channels
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 106:16074-16077, SEP 22 2009
Potassium channels can conduct passively K(+) ions with rates of up to approximate to 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(+).
