ABSTRACT
Ion channel conduction of current across the bilayer membrane relies on the energetics of the channel coupled to the membrane constituents. The channel subunits and membrane materials are associated with each other differently in different regions and course of time. Environmental stimuli, such as voltage, ligand concentration and temperature, cause the membrane-hosted ion channels to respond. Consequently, their catalytic sites, the ion-conducting pores, are found to open and close following specific gating mechanisms. A recent study pointed out that although the active-state conformations of ion channels are known from typical X-ray structures, an atomic resolution structure of any voltage-dependent ion channel in the resting state is not currently available. Ion channels are constructed using channel subunit proteins, peptides, or drugs that have considerable hydrophobic properties relative to their hydrophilic counterparts. Statistical mechanical formulation of the equilibrium properties of selective ion channels was developed by incorporating the influence of the membrane potential, multiple occupancy, and saturation effects about two decades ago.
