CotA laccase, a novel aflatoxin oxidase from Bacillus licheniformis, transforms aflatoxin B1 to aflatoxin Q1 and epi-aflatoxin Q1
CotA laccase, a novel aflatoxin oxidase from Bacillus licheniformis, transforms aflatoxin B1 to aflatoxin Q1 and epi-aflatoxin Q1
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DOI：
10.1016/j.foodchem.2020.126877
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发表时间：
2020-09-30
期刊：
影响因子：
8.8
通讯作者：
Zhao, Lihong
中科院分区：
文献类型：
--
作者：
Guo, Yongpeng;Qin, Xiaojuan;Zhao, Lihong
本研究克隆了地衣芽孢杆菌ANSB821的CotA蛋白，并在大肠杆菌中进行了表达。除了漆酶活性外，我们还发现在没有氧化还原介体的情况下，重组CoTA能够有效地氧化黄曲霉毒素B-1。重组CoTA对黄曲霉毒素B-1的K-m、K-CAT和V-max分别为60.62muM、0.03mgmin(-1)和10.08mgmin(-1)mg(-1)。对COTA介导的黄曲霉毒素B-1降解产物进行纯化，鉴定为黄曲霉毒素Q(1)和表黄曲霉毒素Q(1)。黄曲霉毒素Q(1)和表黄曲霉毒素Q(1)处理人肝细胞L-02不抑制细胞活力和诱导细胞凋亡。分子对接模拟表明，氢键和范德华相互作用对黄曲霉毒素B-1-CoTA的稳定性起着重要作用。本研究的这些发现为CoTA作为一种新的黄曲霉毒素氧化酶在降解食品中的黄曲霉毒素B(1)方面提供了可能的应用前景。
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-1 in the absence of redox mediators. The K-m, K-cat and V-max values of the recombinant CotA towards aflatoxin B-1 were 60.62 mu M, 0.03 s(-1) and 10.08 mu g min(-1) mg(-1), respectively. CotA-mediated aflatoxin B-1 degradation products were purified and identified to be aflatoxin Q(1) and epi-aflatoxin Q(1). The treatment of human liver cells L-02 with aflatoxin Q(1) and epi-aflatoxin Q(1) 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-1-CotA stability. These findings in the current study are promising for a possible application of CotA as a novel aflatoxin oxidase in degrading AFB(1) in food.