Crumpled structure of the custom hydrophobic lytic peptide cecropin B3

The solution structure of a custom lytic peptide, cecropin B3 (CB3), having two identical hydrophobic segments on both the N- and C-termini, was inves tigated by two-dimensional NMR spectroscopy. The need to determine the stru cture of this peptide is rooted in its specific ability to lyse lipid layer s that have a high content of anionic lipid. The lytic activities of CB3 on cell membranes including cancer cells and bacteria is found to be less tha n cecropin B1. The results show that CB3 has four discrete segments forming alpha helical structures. The crumpled structure of CB3 provides evidence for the lysis of the lipid layer being via a pathway that differs from pore formation. The results in this study provide strong clues towards a ration al design for a potent antimicrobial and antitumor peptide.