ABSTRACT
Over the past decade a multitude of peptides with cell lytic activity has been discovered in almost all kinds of species (1-4). The diversity of physiological systems in which the peptides are expressed and their broad-spectrum activities have confirmed their role as offensive and defensive weapons of creatures. Many of these peptides exhibit antimicrobial specificity and have been suggested to constitute a system of innate immunity (2,5-8). These properties have made several compounds promising candidates for the development of a new class of antibiotics (6,9,10). Stimulated by the challenge of bacterial resistance to conventional antibiotics (11-13) and by evidence for anticancer activity (9), considerable effort is being made to understand the structural basis of membrane selectivity and to elucidate the molecular mechanism of action (14,15). The peptides exert their effect by permeabilization of the lipid matrix of the target cell. It is generally accepted that the peptide-membrane interaction is the consequence of several common structural features of the peptides, such as the tendency to adopt an amphipathic conformation, as well as of properties of the anisotropic cell membrane (1,16,17). However, the molecular mechanism of membrane disturbance by the diverse membrane-active peptides is still controversial.
