Molecular and channel-forming characteristics of gramicidin K's: a family of naturally occurring acylated gramicidins.

Overview

The gramicidin K family is a set of naturally occurring acylated linear peptides in which a fatty acid is esterified to the ethanolamine hydroxyl of either gramicidin A or C, and possibly also to gramicidin B (Koeppe, R. E., II, Paczkowski, J. A., & Whaley, W. L. (1985) Biochemistry 24, 2822-2826). These acylated gramicidins form membrane-spanning channels in planar lipid bilayers and therefore constitute a model system with which to study the structural and functional consequences of acylation on membrane proteins. This paper serves to characterize further the channels formed by acylated gramicidins A and C and to demonstrate that these channels are structurally equivalent to the channels formed by the standard gramicidins. We also present additional evidence for the ester linkage in the natural acylated gramicidins A and C and identify the fatty acyl chains.