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 B1 in the absence of redox mediators. The Km, Kcat and Vmax values of the recombinant CotA towards aflatoxin B1 were 60.62 μM, 0.03 s-1 and 10.08 μg min-1 mg-1, respectively. CotA-mediated aflatoxin B1 degradation products were purified and identified to be aflatoxin Q1 and epi-aflatoxin Q1. The treatment of human liver cells L-02 with aflatoxin Q1 and epi-aflatoxin Q1 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 B1-CotA stability. These findings in the current study are promising for a possible application of CotA as a novel aflatoxin oxidase in degrading AFB1 in food.

中文翻译：

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CotA 漆酶是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 B1 转化为黄曲霉毒素 Q1 和表观黄曲霉毒素 Q1。


在本研究中，来自地衣芽孢杆菌ANSB821的CotA蛋白被克隆并在大肠杆菌中表达。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可以有效氧化黄曲霉毒素B1。重组CotA对黄曲霉毒素B1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B1降解产物经纯化并鉴定为黄曲霉毒素Q1和表观黄曲霉毒素Q1。用黄曲霉毒素 Q1 和表观黄曲霉毒素 Q1 处理人肝细胞 L-02 不会抑制细胞活力并诱导细胞凋亡。分子对接模拟表明氢键和范德华相互作用在黄曲霉毒素B1-CotA稳定性中发挥重要作用。当前研究中的这些发现有望将 CotA 作为一种新型黄曲霉毒素氧化酶用于降解食品中的 AFB1。