Table of Contents
Journal of Biophysics
Volume 2016, Article ID 1657679, 10 pages
http://dx.doi.org/10.1155/2016/1657679
Research Article

Self-Optimized Biological Channels in Facilitating the Transmembrane Movement of Charged Molecules

1Institute for Bio-Medical Physics, 109A Pasteur, 1st District, Ho Chi Minh City 710115, Vietnam
2VAST/Institute of Physics, 1 Mac Dinh Chi, 1st District, Ho Chi Minh City 710116, Vietnam

Received 13 October 2015; Revised 13 January 2016; Accepted 27 January 2016

Academic Editor: João A. R. G. Barbosa

Copyright © 2016 V. T. N. Huyen et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We consider an anisotropically two-dimensional diffusion of a charged molecule (particle) through a large biological channel under an external voltage. The channel is modeled as a cylinder of three structure parameters: radius, length, and surface density of negative charges located at the channel interior-lining. These charges induce inside the channel a potential that plays a key role in controlling the particle current through the channel. It was shown that to facilitate the transmembrane particle movement the channel should be reasonably self-optimized so that its potential coincides with the resonant one, resulting in a large particle current across the channel. Observed facilitation appears to be an intrinsic property of biological channels, regardless of the external voltage or the particle concentration gradient. This facilitation is very selective in the sense that a channel of definite structure parameters can facilitate the transmembrane movement of only particles of proper valence at corresponding temperatures. Calculations also show that the modeled channel is nonohmic with the ion conductance which exhibits a resonance at the same channel potential as that identified in the current.