Yang Weinan, Kong Lingxin, Wang Qing, Deng Zixin, You Delin
State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200030, China.
Synth Syst Biotechnol. 2020 Jun 23;5(3):121-130. doi: 10.1016/j.synbio.2020.06.001. eCollection 2020 Sep.
Demecycline (DMTC) and demeclocycline (DMCTC) are C6-demethylated derivatives of tetracycline (TC) and chlortetracycline (CTC), respectively. They are precursors of minocycline and tigecycline, which showed remarkable bioactivity against TC-resistant bacteria and have been used clinically for decades. In order to biosynthesize drug precursors DMTC and DMCTC, the function of a possible C-methyltransferase encoding gene was studied systematically in the CTC high-yielding industrial strain F3. The mutant accumulated two new products, which were turned out to be DMTC and DMCTC. Meanwhile, time-course analysis of the fermentation products detected the epimers of DMTC and DMCTC transformed spontaneously. Finally, an engineering strain with higher productivity of DMCTC was constructed by deleting and overexpressing of three extra copies simultaneously. Construction of these two engineering strains not only served as a successful example of synthesizing required products through metabolic engineering, but also provided original strains for following elaborate engineering to synthesize more effective tetracycline derivatives.
地美环素（DMTC）和去甲金霉素（DMCTC）分别是四环素（TC）和金霉素（CTC）的C6-去甲基化衍生物。它们是米诺环素和替加环素的前体，对耐四环素细菌显示出显著的生物活性，并已在临床上使用了数十年。为了生物合成药物前体DMTC和DMCTC，在CTC高产工业菌株F3中系统研究了一个可能的C-甲基转移酶编码基因的功能。该突变体积累了两种新产物，结果证明是DMTC和DMCTC。同时，对发酵产物的时间进程分析检测到DMTC和DMCTC的差向异构体自发转化。最后，通过同时缺失和过表达三个额外拷贝构建了一株DMCTC产量更高的工程菌株。这两种工程菌株的构建不仅是通过代谢工程合成所需产物的成功范例，也为后续精细工程合成更有效的四环素衍生物提供了原始菌株。
