Crowded Charge in Biological Ion Channels

Biological ion channels are proteins that conduct ions across lipid membranes that are otherwise impermeable to them. Modern theories of electrolyte solutions that include the finite size of the ions has been shown to be a very successful method for modeling ion channels and we continue that work here. We consider a model of ion flux through a calcium-selective ion channel and calculate the components of the chemical potential using density functional theory of electrolyte solutions. For different bath ion concentrations of K and Ca current/voltage curves are computed and the three components of the chemical potentials of the ions are examined.