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Charge fluctuations and their effect on conduction in biological ion channels

FREE ARTICLE Focus on Unsolved Problems of Noise in Physics, Biology and Technology

D G Luchinsky1,2, R Tindjong1, I Kaufman3, P V E McClintock1 and R S Eisenberg4

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Part of Focus on Unsolved Problems of Noise in Physics, Biology and Technology

The effect of fluctuations on the conductivity of ion channels is investigated. It is shown that modulation of the potential barrier at the selectivity site due to electrostatic amplification of charge fluctuations at the channel mouth exerts a leading-order effect on the channel conductivity. A Brownian dynamical model of ion motion in a channel is derived that takes into account both fluctuations at the channel mouth and vibrational modes of the wall. The charge fluctuations are modeled as a shot noise flipping the height of the potential barrier. The wall fluctuations are introduced as a slow vibrational mode of the protein motion that modulates ion conductance both stochastically and periodically. The model is used to estimate the contribution to the conductivity of ion channels coming from the electrostatic amplification of charge fluctuations.


Keywords

diffusion

dynamics (theory)

 

E-print Number: 0807.0838

Cited: by |

Refers: to

PACS

87.15.Ya Fluctuations

87.14.E- Proteins

87.16.Uv Active transport processes

87.19.R- Mechanical and electrical properties of tissues and organs

87.16.D- Membranes, bilayers, and vesicles

MSC

60J65 Brownian motion (See also 58J65)

82C70 Transport processes

82C31 Stochastic methods (Fokker-Planck, Langevin, etc.) (See also 60H10)

92C40 Biochemistry, molecular biology

Subjects

Medical physics

Biological physics

Dates

Issue 01 (January 2009)

Received 7 July 2008, accepted for publication 21 August 2008

Published 5 January 2009



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