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


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

We consider an anisotropically two-dimensional diffusion of a chargedmolecule (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 coincideswith 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.
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  • Self-Optimized Biological Channels in Facilitating the Transmembrane Movement of Charged Molecules

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Authors

V. T. N. Huyen
Institute for Bio-Medical Physics, 109A Pasteur, 1st District, Ho Chi Minh City 710115, Viet Nam
Le Bin Ho
VAST/Institute of Physics, 1 Mac Dinh Chi, 1st District, Ho Chi Minh City 710116, Viet Nam
Vu Cong Lap
Institute for Bio-Medical Physics, 109A Pasteur, 1st District, Ho Chi Minh City 710115, Viet Nam
V. Lien Nguyen
Institute for Bio-Medical Physics, 109A Pasteur, 1st District, Ho Chi Minh City 710115, Viet Nam

Abstract


We consider an anisotropically two-dimensional diffusion of a chargedmolecule (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 coincideswith 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.