Structures and biological activities of new wasp venom peptides isolated from the black-bellied hornet (Vespa...

The black-bellied hornet (Vespa basalis) is the most dangerous species of vespine wasps found in Taiwan. The hornet possesses a highly toxic venom which is rich in toxin, enzymes and biologically active peptides. Using ultrafiltration to remove the high molecular weight toxin and enzymes followed by reverse-phase HPLC, three bioactive tridecapeptides, designated "HP-1, HP-2 and HP-3" were isolated from the venom. Their amino acid sequences were determined as: HP-1: LFRLIAKTLGSLM, HP-2: LFRLLANTLGKIL, HP-3: IFGLLAKTLGNLF. The primary structures of these peptides appear to be homologous to those of chemotactic peptides isolated from other vespid venoms. However, these peptides show little chemotactic activity on human neutrophils and have distinct tripeptide sequences at the amino and carboxylic terminal sides, as compared with other hornet chemotactic peptides. The lack of Pro3 which is a characteristic structure of vespid chemotactic peptides in their sequences is most distinctive. Circular dichroism spectra of these peptides measured in 20% trifluoroethanol show a high content of alpha-helical conformation. All three peptides provoked local edema in rat hind paw, which could be inhibited by antihistamine (diphenhydramine) and drug with antiserotonin activity (cyproheptadine). These peptides also exhibited a potent hemolytic activity which was potentiated by a non-lytic dose of the hornet lethal protein, suggesting a supporting role of these peptides in the lethal effect of Vespa basalis venom.