COMPUTER-SIMULATION OF ION CONDUCTANCE IN MEMBRANE CHANNELS

We present a method for calculation of electric forces in biological c hannels, which facilitates microscopic modeling of ion transport in ch annels using computer simulation. The method is based on solving Poiss on's equation on a grid and storing the electric potential and field f or various configurations in a table. During simulations, the potentia l and field at any point are calculated by interpolating between table entries rather than solving Poisson's equation. This speeds up comput er simulations by orders of magnitude with minimal loss in accuracy. W ith this method, one can run simulations long enough to determine the channel conductance, which can be compared directly with experimental data. Since conductance is the most important observable quantity in d escription of membrane channels, this method will be very useful in fu ture simulation studies of channels.