Poly(DL-proline), a synthetic polypeptide behaving as an ion channel across bilayer membranes

The synthesis and characterization of poly(DL-proline) are reported in relation with its predicted property of forming ion channels across membranes. The analysis of the conductance induced in synthetic bilayer membranes doped with poly(DL-proline) shows ionic permeoselectivity and the characteristic time course of fluctuations of ion channels, according to the similarity with the active structure of gramicidin A in membranes during the ion passage. An alternative mechanism of ion transport across bilayer membranes is also advanced.