Synthesis and ionic channels of a linear gramicidin containing naphthylalanine instead of tryptophan

Naphthylalanine gramicidin A was prepared by the solid phase method using an aminopolyacrylic resin after optical resolution of (D, L) naphthylalanine by enzymatic methods. Removal of the peptide from the resin was achieved by transesterification of the succinic ester linkage. Infrared spectroscopy indicated that the presence of naphthylalanine strongly modifies the monomer-dimer equilibrium. Single-channel measurements suggested that the conductance of the gramicidin channel can be governed by the dipole moment of the aromatic side-chains.