Li Xiangfei, Yu Fei, Wang Fang, Wang Sang, Han Rumeng, Cheng Yihan, Zhao Ming, Sun Junfeng, Xue Zhenglian
Engineering Laboratory for Industrial Microbiology Molecular Beeding of Anhui Province, College of Biologic and Food Engineering, Anhui Polytechnic University, 8 Middle Beijing Road, Wuhu, 241000, China.
The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China.
Bioresour Bioprocess. 2022 Dec 5;9(1):123. doi: 10.1186/s40643-022-00613-4.
Neomycin, an aminoglycoside antibiotic with broad-spectrum antibacterial resistance, is widely used in pharmaceutical and agricultural fields. However, separation and purification of neomycin B as an active substance from Streptomyces fradiae are complicated. Although NeoN can catalyze conversion of neomycin C to neomycin B, the underlying catalytic mechanism is still unclear. In this study, the genomic information of high-yielding mutant S. fradiae SF-2 was elucidated using whole-genome sequencing. Subsequently, the mechanism of NeoN in catalyzing conversion of neomycin C to neomycin B was resolved based on NeoN-SAM-neomycin C ternary complex. Mutant NeoN showed improved NeoN activity, and the recombinant strain SF-2-NeoN accumulated 16,766.6 U/mL neomycin B, with a decrease in neomycin C ratio from 16.1% to 6.28%, when compared with the parental strain SF-2. In summary, this study analyzed the catalytic mechanism of NeoN, providing significant reference for rational design of NeoN to improve neomycin B production and weaken the proportion of neomycin C.
新霉素是一种具有广谱抗菌抗性的氨基糖苷类抗生素，广泛应用于制药和农业领域。然而，从弗氏链霉菌中分离和纯化作为活性物质的新霉素B很复杂。尽管NeoN可以催化新霉素C转化为新霉素B，但其潜在的催化机制仍不清楚。在本研究中，使用全基因组测序阐明了高产突变株弗氏链霉菌SF-2的基因组信息。随后，基于NeoN-SAM-新霉素C三元复合物解析了NeoN催化新霉素C转化为新霉素B的机制。与亲本菌株SF-2相比，突变型NeoN表现出更高的NeoN活性，重组菌株SF-2-NeoN积累了16766.6 U/mL的新霉素B，新霉素C的比例从16.1%降至6.28%。总之，本研究分析了NeoN的催化机制，为合理设计NeoN以提高新霉素B产量和降低新霉素C比例提供了重要参考。
