Biological activities of C-terminal 15-residue synthetic fragment of melittin: design of an analog with improved antibacterial activity

Melittin, the 26-residue predominant toxic peptide from bee venom, exhibits potent antibacterial activity in addition to its hemolytic activity. The s ynthetic peptide of 15 residues corresponding to its C-terminal end (MCF), which encompasses its most amphiphilic segment, is now being shown to posse ss antibacterial activity about 5-7 times less compared to that of melittin , MCF, however, is 300 times less hemolytic. An analog of MCF, MCFA, in whi ch two cationic residues have been transpositioned to the N-terminal region from the C-terminal region, exhibits antibacterial activity comparable to that of melittin, but is only marginally more hemolytic than MCF. The bioph ysical properties of the peptides, like folding and aggregation, correlate well with their biological properties. (C) 1999 Federation of European Bioc hemical Societies.