Detoxification of ochratoxin A by Lysobacter sp. CW239 and characteristics of a novel degrading gene carboxypeptidase cp4
Detoxification of ochratoxin A by Lysobacter sp. CW239 and characteristics of a novel degrading gene carboxypeptidase cp4
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溶杆菌属 (Lysobacter sp.) 对赭曲霉毒素 A 的解毒作用
DOI：
10.1016/j.envpol.2019.113677
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发表时间：
2020
影响因子：
8.9
通讯作者：
Zhou Yu
中科院分区：
文献类型：
--
作者：
Wei Wei;Qian Yingying;Wu Yanbo;Chen Ying;Peng Cheng;Luo Mingzhong;Xu Junfeng;Zhou Yu
赭曲霉毒素A（OTA）是一种强有力的真菌毒素，经常污染农产品，威胁食品安全。一株高效OTA降解菌Lysoacetum sp.对CW 239进行了分离纯化，并研究了其对OTA的降解特性。从CW 239菌株中成功克隆并鉴定了一个新的OTA降解基因carboxypeptidasecp 4。将基因p4和表达载体pET-32a（+）构建成异源重组子，并在大肠杆菌BL 21 CodonPlus™（DE 3）中高效表达。纯化重组蛋白rCP 4，并测定其对OTA的降解活性。CW 239对OTA有较好的降解效果（24 h降解率为86.2%），但在较高蛋白浓度（0.25 mg/mL）下，对rCP 4的24 h降解率仅为36.8%。经免疫亲和柱（IAC）纯化后，经质谱（MS）鉴定，得到了毒性较低的赭曲霉毒素α（OTα）。本研究的系列研究表明，在该降解菌中，CP 4可能与另一种未知降解剂同时共降解OTA。
Ochratoxin A (OTA) is a potent mycotoxin that frequently contaminates agro-products and threatens food safety. A highly efficient OTA degrading strainLysobactersp. CW239 was isolated, and the OTA degradation characteristics were investigated. A novel OTA degrading gene carboxypeptidasecp4was successfully cloned and characterized from CW239. The heterologous recombinant was constructed by genecp4and expression vector pET-32a(+)and overexpressed byE. coliBL21 CodonPlus™ (DE3). The recombinant protein rCP4 was purified, and the OTA-degrading activity was evaluated. Although OTA was efficiently degraded by CW239 (24-h degradation ratio of 86.2%), the 24-h OTA degradation ratio for rCP4 was only 36.8% at fairly high concentration (0.25 mg/mL) protein. The degraded product was obtained by immune affinity column (IAC) and determined by mass spectrometry (MS), and the degraded product was the less toxic ochratoxin α (OTα). Based on the serial investigations of this study, OTA might be simultaneously co-degraded by CP4 and another unknown degrading agent in that degrading strain.