A combined molecular dynamics and diffusion model of single proton conduction through gramicidin.
We develop a model for proton conduction through gramicidin based on the molecular dynamics simulations of Pomès and Roux (Biophys. J. 72:A246, 1997). The transport of a single proton through the gramicidin pore is described by a potential of mean force and diffusion coefficient obtained from the molecular dynamics. In addition, the model incorporates the dynamics of a defect in the hydrogen bonding structure of pore waters without an excess proton. Proton entrance and exit were not simulated by the molecular dynamics. The single proton conduction model includes a simple representation of these processes that involves three free parameters. A reasonable value can be chosen for one of these, and the other two can be optimized to yield a good fit to the proton conductance data of, Ann. N.Y. Acad. Sci. 339:8-20) for pH > or = 1.7. A sensitivity analysis shows the significance of this fit.
Schumaker
M F
MF
Department of Pure and Applied Mathematics, Washington State University, Pullman, Washington 99164-3113, USA. schumaker@wsu.edu
Pomès
R
R
Roux
B
B
D001703:Biophysics / Q000379:methods; D004058:Diffusion; D006096:Gramicidin / Q000737:chemistry*; D006860:Hydrogen Bonding; D007700:Kinetics; D008954:Models, Biological; D008962:Models, Theoretical; D011522:Protons
D011522:Protons; D006096:Gramicidin