芽孢杆菌漆酶，一种来自地衣芽孢杆菌的新型黄曲霉毒素氧化酶，可将黄曲霉毒素B转化为黄曲霉毒素Q和表黄曲霉毒素Q。
CotA laccase, a novel aflatoxin oxidase from Bacillus licheniformis, transforms aflatoxin B to aflatoxin Q and epi-aflatoxin Q.
作者信息
Guo Yongpeng, Qin Xiaojuan, Tang Yu, Ma Qiugang, Zhang Jianyun, Zhao Lihong
机构信息
State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, PR China.
State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, PR China.
出版信息
Food Chem. 2020 Apr 21;325:126877. doi: 10.1016/j.foodchem.2020.126877.
In the present study, the CotA protein from Bacillus licheniformis ANSB821 was cloned and expressed in Escherichia coli. Apart from the laccase activities, we found that the recombinant CotA could effectively oxidize aflatoxin B in the absence of redox mediators. The K, K and V values of the recombinant CotA towards aflatoxin B were 60.62 μM, 0.03 s and 10.08 μg min mg, respectively. CotA-mediated aflatoxin B degradation products were purified and identified to be aflatoxin Q and epi-aflatoxin Q. The treatment of human liver cells L-02 with aflatoxin Q and epi-aflatoxin Q did not suppress cell viability and induce apoptosis. Molecular docking simulation revealed that hydrogen bonds and van der Waals interaction played an important role in aflatoxin B-CotA stability. These findings in the current study are promising for a possible application of CotA as a novel aflatoxin oxidase in degrading AFB in food.
在本研究中，地衣芽孢杆菌ANSB821的CotA蛋白在大肠杆菌中被克隆并表达。除了漆酶活性外，我们发现重组CotA在没有氧化还原介质的情况下能够有效氧化黄曲霉毒素B。重组CotA对黄曲霉毒素B的Km、kcat和Vmax值分别为60.62 μM、0.03 s-1和10.08 μg min-1 mg-1。CotA介导的黄曲霉毒素B降解产物被纯化并鉴定为黄曲霉毒素Q和表黄曲霉毒素Q。用黄曲霉毒素Q和表黄曲霉毒素Q处理人肝细胞L-02不会抑制细胞活力和诱导凋亡。分子对接模拟表明，氢键和范德华相互作用在黄曲霉毒素B-CotA稳定性中起重要作用。本研究中的这些发现有望使CotA作为一种新型黄曲霉毒素氧化酶在食品中降解AFB方面得到应用。
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