호박벌 유래 디펜신 유전자의 분자적 특성분석 및 항균 활성

Antimicrobial peptides of insects are found and reported as immune defence system against infectious agents. The peptides are produced by fat body cells and thrombocytoids, a blood cell type. Defensin is 38-45 amino acids long and consists of an α-helix linked by a loop to an antiparallel β-sheet. Defensin from a bumblebee, Bombus ignitus, is known to comprise 52 amino acid residues. This peptide consists of two α-helixes; ACAANCLSM and KTNFKDLWDKRF and one β-sheet; GGRCENGVCLCR. We carried out antibacterial activity test by radial diffusion assay against Staphylococcus aureus (Gram positive), Escherichia coli (Gram negative), Pseudomonas syringae (Gram negative), Candida albicans (fungi), MDRPA, MRSA, and VRE (antimicrobial resistant microbes) with synthetic oligopeptides from Peptron (Daejeon, Korea). The predicted curtailment fragment (GGRCEVCLCR-NH2) for β-sheet had strong antibacterial activity when internal amino acids were removed. But, curtailment fragments (ACAANCLSM-NH2 and TNFKDLWDKR-NH2) of α-helix were not showed antibacterial activity. These synthetic oligopeptides were showed the great activity against Gram positive and negative bacteria.