Antimicrobial and hemolytic activities of crabrolin, a 13-residue peptide from the venom of the European hornet, Vespa crabro, and its analogs.

The venom of insects like bee, hornet and wasp contain peptides that exhibit potent biological activities. Many of these peptides are composed of 13-26 residues and are thus accessible through chemical synthesis as well as amenable to studies directed toward structure-function correlations. In this report, we describe antibacterial and hemolytic activities of crabrolin: FLPLILRKIVTAL-NH2, a 13-residue-peptide present in the venom of the hornet Vespa crabro and related peptides. The analogs were chosen so that the role of proline and positively charged amino acids in modulating biological activities could be evaluated. Our results indicate that, although helical conformation is necessary for hemolytic activity, it is not a prerequisite for antibacterial activity. Appropriately positioned, charged and hydrophobic residues and overall hydrophobicity appear to determine antibacterial activity. The discovery of a large number of host-defense peptides in a variety of species in recent years offers a large repertoire of molecules that can be "engineered" based on biophysical principles to yield molecules with specific activities.