Voltage-dependent and multi-state ionic channels induced by trichorzianines, anti-fungal peptides related to alamethicin.

The ionophore properties of two peptaibols of the trichorzianine family have been investigated in planar lipid bilayers and compared to those of alamethicin. Macroscopic conductance experiments reveal voltage-dependent channels only in the thinnest membranes and a greater efficiency of the neutral analog. In single-channel experiments, a multi-state behaviour, consistent with the usual barrel-stave model, is disclosed but the discrete current fluctuations are much more rapid than for alamethicin. The results indicate a stringent requirement for the helix length/bilayer thickness match in agreement with a previous model and suggest the design of new synthetic peptides.