Model calculations of polarization effects in elastic membrane channels

Molecular channels embedded in biological membranes are extremely well balanced systems, because the dielectric barrier imposed on an ion's self-energy, which would make the membrane practically impenetrable, is locally cancelled by the interaction of the ion with the channel up to a few kT at room temperature. This purpose can serve only highly specialized systems with a certain ligand configuration and appropriate properties. In this article two different models are tested with respect to their polarization properties and discussed in detail, one for ionic polarization and the other for dipolar polarization. The channel-mediated attractive forces between two ions are also investigated in both cases.