Mastoparan-like peptide 12a

Peptide agents are regarded as potential candidates for overcoming the life-threatening resistance of pathogenic microorganisms to classic antibiotics. Accordingly, a peptidomic and genomic investigation of natural antimicrobial peptides (AMPs) can provide structure-functional information for designing peptide antibiotics with therapeutic potential. In the present study, we identified nine AMPs from the venom gland of the wasp Vespa tropica using combined methods of peptidomics and genomics. These AMPs were classified into two different families based on sequence similarity, mastoparan and vespid chemotactic peptides (VCPs), and thus named mastoparan-VT1 to -VT7, VCP-VT1 and -VT2. Among these nine AMPs, mastoparan-VT1 and VCP-VT1 are identical to peptides from other wasps. These AMPs exerted broad-spectrum antimicrobial activity against standard and clinically isolated strains of bacteria. In addition, they showed weak hemolytic activity toward human erythrocytes. Our results reveal that identical AMPs are widely distributed in different wasp venoms and might provide templates for the development of novel peptide antibiotics.

Hornets possess highly toxic venoms, which are rich in toxins, enzymes and biologically active peptides. Many bioactive substances have been identified from wasp venoms. Vespa mastoparan (MP-VBs) and Vespa chemotatic peptide presenting antimicrobial action (VESP-VBs) were purified and characterized from the venom of the wasp, Vespa bicolor Fabricius. The precursors encoding VESP-VBs and MP-VBs were cloned from the cDNA library of the venomous glands. Analyzed by FAB-MS, the amino acid sequence and molecular mass for VESP-VB1 were FMPIIGRLMSGSL and 1420.6, for MP-VB1 were INMKASAAVAKKLL and 1456.5, respectively. The primary structures of these peptides are homologous to those of chemotactic peptides and mastoparans isolated from other vespid venoms. These peptides showed strong antimicrobial activities against bacteria and fungi and induced mast cell degranulation, but displayed almost no hemolytic activity towards human blood red cells.

Hornets possess highly toxic venoms, which are rich in toxin, enzymes and biologically active peptides. Many bioactive substances have been identified from wasp venoms but only a few serine protease inhibitors have been identified from two kinds of wasp venoms. In this work, a serine protease inhibitor named bicolin was purified and characterized from the venom of the wasp, Vespa bicolor Fabricius. The precursor encoding bicolin was cloned from the cDNA library of the venomous glands. It is a cysteine-rich small protein containing 54 amino acid residues including 6 half-cysteines. The peptide is homologous to serine protease inhibitors isolated from venoms of Anoplius samariensis and Pimpla hypochondriaca. Bicolin showed inhibitory ability against trypsin and thrombin.