Antimicrobial activity of a honeybee (Apis cerana) venom Kazal-type serine protease inhibitor
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- 作者：Bo Yeon Kim ; Kwang Sik Lee ; Feng Ming Zou ; Hu Wan ; Yong Soo Choi ; Hyung Joo Yoon ; Hyung Wook Kwon ; Yeon Ho Je ; Byung Rae Jin
- 关键词：Apis cerana ; Honeybee ; Kazal-type serine protease inhibitor ; Microbial serine protease inhibitor ; Venom ; Antimicrobial activity
- 刊名：Toxicon
- 出版年：15 December, 2013
- 年：2013
- 卷：76
- 期：Complete
- 页码：110-117
- 全文大小：1233 K
文摘
Insect-derived Kazal-type serine protease inhibitors exhibit thrombin, elastase, plasmin, proteinase K, or subtilisin A inhibition activity, but so far, no functional roles for bee-derived Kazal-type serine protease inhibitors have been identified. In this study, a bee (Apis cerana) venom Kazal-type serine protease inhibitor (AcKTSPI) that acts as a microbial serine protease inhibitor was identified. AcKTSPI contained a single Kazal domain that displayed six conserved cysteine residues and a P1 threonine residue. AcKTSPI was expressed in the venom gland and was present as a 10-kDa peptide in bee venom. Recombinant AcKTSPI Kazal domain (AcKTSPI-Kd) expressed in baculovirus-infected insect cells demonstrated inhibitory activity against subtilisin A (Ki 67.03聽nM) and proteinase K (Ki 91.53聽nM), but not against 伪-chymotrypsin or trypsin, which implies a role for AcKTSPI as a microbial serine protease inhibitor. However, AcKTSPI-Kd exhibited no detectable inhibitory effects on factor Xa, thrombin, tissue plasminogen activator, or elastase. Additionally, AcKTSPI-Kd bound directly to Bacillus subtilis, Bacillus thuringiensis, Beauveria bassiana, and Fusarium graminearum but not to Escherichia coli. Consistent with these findings, AcKTSPI-Kd showed antibacterial activity against Gram-positive bacteria and antifungal activity against both plant-pathogenic and entomopathogenic fungi. These findings constitute molecular evidence that AcKTSPI acts as an inhibitor of microbial serine proteases. This paper provides a novel view of the antimicrobial functions of a bee venom Kazal-type serine protease inhibitor.