Model illustration: the whole system is divided into two subdomains, the solvent domain Ω s and membrane/channel domain Ω s . Multiscale treatments and multiphysics descriptions are applied in corresponding subdomains and materials. The z-direction is considered as the proton transport direction. Profile of water in the channel pore is not displayed.
Different strategies on treatment of proton-water interaction model.
Work flow of the overall surface driven self-consistent iteration.
A typical Lennard-Jones kernel and its interaction property in the bulk water.
A 1D demonstration of geometric confinement effects on ion-water interaction potential energy. Channel width is represented between the two vertical dashed lines. (a) A narrow channel; (b) A wide channel.
A 1D demonstration of geometric confinement effects on ion-water interaction with different water density distribution. Channel width is represented between the two vertical dashed lines. (a) Constant water density and energy profile; (b) Water density in Gaussian distribution and energy profile.
3D illustration of the Gramicidin A (GA) channel structure and surface electrostatic potential. The negative surface electrostatics as indicated by the intensive red color on the channel upper surface and inside the channel pore implies that the GA selects positive ions. (a) Top view of the GA channel; (b) Side view of the GA channel.
Electrostatic potential of the GA channel along the z-axis obtained with ε m = 5 and M (Red: εch = 20; Green: εch = 40; Blue: εch = 80).
Calculated generalized correlation mapped on the 3D GA channel surface. The positive surface generalized correlation as indicated by the intensive blue color on the channel upper surface and inside the channel pore implies that the GC usually generates a repulsive force. (a) Top view of the GA channel; (b) Side view of the GA channel.
Generalized correlation potentials of the GA channel along the z-axis.
Total potential energy of the GA channel, including electrostatic and generalized correlation contributions under various voltage biases. The pH value of solution is 2.75. (a) Total potential of monovalent cations; (b) Total potential of monovalent anions.
Voltage-current relation of proton translocation of GA at different concentrations. Blue dots: experimental data of Eisenman et al. (Ref. 3); Red solid curves: QDC model prediction.
Conductance-concentration relation of proton translocation at a fixed voltage. Voltage bias = 0.05 V; Blue triangles: experimental data of Eisenman et al. (Ref. 3); Red curve: QDC model prediction.
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