SELECTIVITY OF IONIC CHANNELS - AS SEEN THROUGH COMPUTER-SIMULATION

A theoretical approach has been attempted to study the selectivity of ionic channels in membranes. We predict the channel to behave as an allosteric enzyme and have different conformational states that can bind strongly or weakly to a particular ion. The kinetic equation derived for the channel has few empirical parameters like the allostery factor, the probability factor, binding affinity factor and the transporting rate factor, the later two giving an idea of the ion-ion interactions and ion-channel interactions. The equation is programmed for an IBM compatible personal computer in MS-FORTRAN and the simulation data has been analysed to explain selectivity of the channels to particular ion. The simulation results show that the ions smaller than the permeable ions tend to act as inhibitors, the amplitude depending on the concentrations of the ions and comparative transport rate of the ion in the channel. The program helps easy study of the different parameters on the conducting rate of the permeable ion through the channel which otherwise would demand intricate experimental set-ups.