  The motion of molecules across channels is critically important for
understanding mechanisms of cellular processes. Here we investigate the
mechanism of interactions in the molecular transport by analyzing exactly
solvable discrete stochastic models. It is shown that the strength and spatial
distribution of molecule/channel interactions can strongly modify the particle
current. Our analysis indicates that the most optimal transport is achieved
when the binding sites are near the entrance or exit of the pore. In addition,
the role of intermolecular interactions is studied, and it is argued that an
increase in flux can be observed for some optimal interaction strength. The
mechanism of these phenomena is discussed.
