Tindjong, R. and Luchinsky, D. G. and McClintock, P. V. E. and Eisenberg, R. S. (2009) Charge fluctuations and boundary conditions of biological ion channels : effect on the ionic transition rate. AIP Conference Proceedings, 1129. pp. 535-538. ISSN 0094-243X
Abstract
A self-consistent solution is derived for the Poisson-Nernst-Planck (PNP) equation, valid both inside a biological ion channel and in the adjacent bulk fluid. An iterative procedure is used to match the two solutions together at the channel mouth. Charge fluctuations at the mouth are modeled as shot noise flipping the height of the potential barrier at the selectivity site. The resultant estimates of the conductivity of the ion channel are in good agreement with Gramicidin experimental measurements and they reproduce the observed current saturation with increasing concentration.