Temperature dependence of single channel currents and the peptide libration mechanism for ion transport through the gramicidin A transmembrane channel.

A study of the temperature dependence of gramicidin A conductance of K+ in diphytanoyllecithin/n-decane membranes shows the plot of In (single channel conductance) as a function of reciprocal temperature to be nonlinear for the most probable set of conductance states. These results are considered in terms of a series of barriers, of the dynamics of channel conformation, vis-a-vis the peptide libration mechanism, and of the effect of lipid viscosity on side chain motions again as affecting the energetics of peptide libration.