Isolation and Characterization of a New Member of the Insect Defensin Family from a Beetle, Allomyrina dichotoma

• Published in: Biochemical and biophysical research communications 1996-03, Vol.220 (3), p.526-531
• Main Authors: Miyanoshita, Akihiro, Hara, Seiichi, Sugiyama, Masao, Asaoka, Ai, Taniai, Kiyoko, Yukuhiro, Fumiko, Yamakawa, Minoru
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - isolation & purification; Anti-Bacterial Agents - pharmacology; Bacillus subtilis - drug effects; Blood Proteins - chemistry; Blood Proteins - isolation & purification; Blood Proteins - pharmacology; Coleoptera; Conserved Sequence; Cystine; Defensins; Escherichia coli - drug effects; Gram-Negative Bacteria - drug effects; Gram-Positive Bacteria - drug effects; Larva; Mass Spectrometry; Microbial Sensitivity Tests; Molecular Sequence Data; Pseudomonas aeruginosa - drug effects; Sequence Homology, Amino Acid; Species Specificity; Staphylococcus aureus - drug effects
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1006/bbrc.1996.0438

A new family member of insect defensin, an antibacterial peptide, has been isolated from larvae of a beetle, Allomyrina dichotoma. The peptide consisted of 43 amino acids and 6 cystein residues were conserved in the same position as that of other insect defensins. The new defensin was found to be inducible by bacterial injection. Analysis of the antibacterial spectrum of A. dichotoma defensin indicated that this peptide showed antibacterial activity against Gram-positive bacteria like Staphylococcus aureus and Bacillus subtilis but not against Gram-negative bacteria like Escherichia coli and Pseudomonas aeruginosa, indicating a typical spectrum of the insect defensin family. In addition, A. dichotoma defensin also exhibited antibacterial activity against methicillin-resistant S. aureus (MRSA) isolated from a patient.