A defensin antimicrobial peptide from the venoms of Nasonia vitripennis.

Although many antimicrobial components (i.e. antimicrobial peptides) have been found in many social Hymenoptera venoms, no antimicrobial compound is purified and characterized from parasitic Hymenoptera. From the venoms of the ectoparasitic wasp, Nasonia vitripennis, a defensin-like antimicrobial peptide named defensin-NV was purified and characterized. Defensin-NV is composed of 52 amino acid residues including 6 cysteines forming 3 disulfide bridges. Its amino acid sequence is VTCELLMFGGVVGDSACAANCLSMGKAGGSCNGGLCDCRKTTFKELWDKRFG. By BLAST search, defensin-NV showed significant sequence similarity to other insect defensin antimicrobial peptides. Defensin-NV exerted strong antimicrobial activity against tested microorganisms including Gram-positive bacteria, Gram-negative bacteria and fungi. The cDNA encoding defensin-NV was cloned from the venom reservoir cDNA library of N. vitripennis. The current work firstly purified and characterized an antimicrobial peptide from parasitic Hymenoptera.