A bumblebee (Bombus ignitus) venom serine protease inhibitor that acts as a microbial serine protease inhibitor

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• 作者：Hu Wan ; Bo Yeon Kim ; Kwang Sik Lee ; Hyung Joo Yoon ; Kyung Yong Lee ; Byung Rae Jin
• 关键词：Antimicrobial activity ; Bumblebee ; Bombus ignitus ; Serine protease inhibitor ; Venom
• 刊名：Comparative Biochemistry and Physiology, Part B
• 出版年：January, 2014
• 年：2014
• 卷：167
• 期：Complete
• 页码：59-64
• 全文大小：817 K

文摘

Serine protease inhibitors from bumblebee venom have been shown to block plasmin activity. In this study, we identified the protein BiVSPI from the venom of Bombus ignitus to be a serine protease inhibitor and an antimicrobial factor. BiVSPI is a 55-amino acid mature peptide with ten conserved cysteine residues and a P1 methionine residue. BiVSPI is expressed in the venom gland and also found in the venom as an 8-kDa peptide. Recombinant BiVSPI that was expressed in baculovirus-infected insect cells exhibited inhibitory activity against chymotrypsin but not trypsin. BiVSPI also inhibited microbial serine proteases, such as subtilisin A (K_i = 6.57 nM) and proteinase K (K_i = 7.11 nM). In addition, BiVSPI was shown to bind directly to Bacillus subtilis, Bacillus thuringiensis, and Beauveria bassiana but not to Escherichia coli. Consistent with these results, BiVSPI exhibited antimicrobial activity against Gram-positive bacteria and fungi. These findings provide evidence for a novel serine protease inhibitor in bumblebee venom that has antimicrobial functions.