Analytical models of calcium binding in a calcium channel

摘要: The anomalous mole fraction effect of L-type calcium channels is analyzed using a Fermi like distribution with the experimental data Almers and McCleskey [J. Physiol.353, 585 (1984)] atomic resolution model Lipkind Fozzard [Biochemistry40, 6786 (2001)] selectivity filter channel. Much analysis algebraic, independent differential equations. derived from configuration entropy ions water molecules different sizes, valences, interstitial voids between particles. It allows us to calculate potentials distances (between binding ion oxygen glutamate side chains) directly algebraic formulas. spatial these results comparable those molecular models, but course accuracy no better than that implied by data. chains in our are flexible enough accommodate types bath conditions. curves Na + Ca2+ for [CaCl2] ranging 10−8 10−2 M fixed 32 mM background [NaCl] shown agree published Monte Carlo simulations. Poisson-Fermi equation—that includes both steric correlation effects—is then used obtain profiles energy, concentration, dielectric coefficient solvent region filter. energy depend sensitively on not taken into account classical rate theory. We improve theory introducing lumps effects excluded volumes all empty spaces particles created Lennard-Jones type electrostatic forces. show landscape varies significantly concentrations. constant.