Expression and functional identification of two homologous nicotine dehydrogenases, NicA2 and Nox, from Pseudomonas sp. JY-Q

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Authors
Li, Jun
Shen, Mingjie
Chen, Zeyu
Pan, Fanda
Yang, Yang
Shu, Ming
Chen, Guoqing
Jiao, Yang
Zhang, Fuming
Linhardt, Robert J.
Issue Date
2021-02-01
Type
Article
Language
ENG
Keywords
Biology , Chemistry and chemical biology , Chemical and biological engineering , Biomedical engineering
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Abstract
Nicotine contamination in tobacco waste effluent (TWE) from tobacco industry is a serious threat to public health and environment. Microbial degradation is an impending approach to remove nicotine and transform it into some other high value chemicals. Pseudomonas sp. JY-Q exhibits high efficiency of degradation, which can degrade 5 g/L of nicotine within 24 h. In strain JY-Q, we found the co-occurrence of two homologous key enzymes NicA2 and Nox, which catalyze nicotine to N-methylmyosmine, and then to pseudooxylnicotine via simultaneous hydrolysis. In this study, recombinant NicA2 and Nox were expressed in E. coli BL21(DE3) and purified. In vitro, the activity of recombinant NicA2 and Nox was accelerated by adding co-factor NAD+, suggesting that they worked as dehydrogenases. The optimal reaction conditions, substrate affinity, catabolism efficiency, pH-stability and thermal-stability were determined. Nox showed lower efficiency, but at a higher stability level than NicA2. Nox exhibited wider pH range and higher temperature as optimal conditions for the enzymatic reaction. In addition, The Nox showed higher thermo-stability and acid-stability than that of NicA2. The study on enzymatic reaction kinetics showed that Nox had a lower Km and higher substrate affinity than NicA2. These results suggest that Nox plays more significant role than NicA2 in nicotine degradation in TWE, which usually is processed at low pH (4–5) and high temperature (above 40 °C). Genetic engineering is required to enhance the affinity and suitability of NicA2 for an increased additive effect on homologous NicA2 and Nox in strain JY-Q.
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Protein Expression and Purification, 178, 105767
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Full Citation
Expression and functional identification of two homologous nicotine dehydrogenases, NicA2 and Nox, from Pseudomonas sp. JY-Q, J. Li, M. Shen, Z. Chen, F. Pan, Y. Yang, M. Shu, G. Chen, Y. Jiao, F. Zhang, R. J. Linhardt, W. Zhong, Protein Expression and Purification, 178, 105767 2021.
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10960279
10465928
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