Isolation and molecular cloning of venom peptides from Orancistrocerus drewseni (Hymenoptera: Eumenidae)

Three venom peptides (OdVP1, OdVP2 and OdVP3) were isolated from the venom of the solitary wasp Orancistrocerus drewseni (Hymenoptera: Eumenidae). The mature venom peptide sequences were determined via ESI-Q-TOF MS/MS and by searching the O. drewseni venom gland/sac-specific EST library. All of the OdVPs shared the typical characteristics of amidated C-termini proteins and contained a high content of hydrophobic and positively charged amino acids, suggesting that they adopt an amphipathic α-helical secondary structure, as is the case for mastoparan from Vespula lewisii. The cDNA sequence of the OdVP1 precursor was obtained by 5′- and 3′-rapid amplification of cDNA ends (RACE), and the OdVP2 and OdVP3 precursor transcripts were identified from the venom gland/sac-specific EST library. While the mature peptide sequences were distinct from one another, the overall transcript structure of the OdVPs showed a high homology to that of mastoparan-B from Vespa basalis in that they contained a signal sequence, a prosequence, a mature peptide and a C-terminal glycine. The OdVPs, particularly OdVP2 and OdVP2L (an analog of OdVP2), exhibited strong antifungal activities, but poor antibacterial activities. OdVP2L, which possessed additional Glu-Pro residues, did not have antimicrobial activity against bacteria or Gram-positive yeast but retained activity against Botrytis cinerea.