N-acetyl gramicidin: single-channel properties and implications for channel structure.

Substitution of a methyl group for the N-terminal hydrogen of gramicidin greatly increased the rate of dissociation of conductive channels in lipid bilayer membranes. The finding of short lifetimes for conductive channels, comparable to those seen for the neuromuscular junction, lends support to the head-to-head dimer structure for the conductive channel.