Point mutation of V252 in neomycin C epimerase enlarges substrate-binding pocket and improves neomycin B accumulation in Streptomyces fradiae

Autor: Xiangfei Li, Fei Yu, Fang Wang, Sang Wang, Rumeng Han, Yihan Cheng, Ming Zhao, Junfeng Sun, Zhenglian Xue
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Bioresources and Bioprocessing, Vol 9, Iss 1, Pp 1-13 (2022)
Druh dokumentu: article
ISSN: 2197-4365
DOI: 10.1186/s40643-022-00613-4
Popis: Abstract 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 NeoNV252A showed improved NeoN activity, and the recombinant strain SF-2-NeoNV252A 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. Graphical Abstract
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