Synthetic Channel-forming Peptides and Ion Selectivity

摘要

Peptides made up of alternating L- and D- amino acids can form β-helices as in gramicidin A or cyclic peptides that aggregate to form tubes [1]. In both cases the structures are hollow with all the side chains projecting outwards. Kennedy et al. [2] postulated that peptides having the (LLLD)_n configuration could form helices with every fourth side chain projecting inward. It is a fact that synthetic N-formyl-(LeuSerLeuGly)_ 6—OH, when added to a lipid bilayer, dimerizes, to form ion channels having conductances greater than that of gramicidin.