Conversion of nornicotine to 6-hydroxy-nornicotine and 6-hydroxy-myosmine by Shinella sp. strain HZN7
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- 作者：Jiguo Qiu ; Na Li ; Zhenmei Lu ; Youjian Yang…
- 关键词：Nornicotine ; 6 ; Hydroxy ; nornicotine ; 6 ; Hydroxy ; myosmine ; 6 ; Hydroxy ; pseudooxy ; nornicotine ; Nicotine dehydrogenase ; 6 ; Hydroxy ; nicotine oxidase ; Shinella sp. HZN7
- 刊名：Applied Microbiology and Biotechnology
- 出版年：2016
- 出版时间：December 2016
- 年：2016
- 卷：100
- 期：23
- 页码：10019-10029
- 全文大小：1,700 KB
- 刊物类别：Chemistry and Materials Science
- 刊物主题：Chemistry
Biotechnology
Microbiology
Microbial Genetics and Genomics - 出版者：Springer Berlin / Heidelberg
- ISSN：1432-0614
- 卷排序：100
文摘
Nornicotine is a natural alkaloid produced by plants in the genus Nicotiana and is structurally related to nicotine. Importantly, nornicotine is the direct precursor of tobacco-specific nitrosamine N′-nitrosonornicotine, which is a highly potent human carcinogen. Microbial detoxification and degradation of nicotine have been well characterized; however, until now, there has been no information on the molecular mechanism of nornicotine degradation. In this study, we demonstrate the transformation of nornicotine by the nicotine-degrading strain Shinella sp. HZN7. Three transformation products were identified as 6-hydroxy-nornicotine, 6-hydroxy-myosmine, and 6-hydroxy-pseudooxy-nornicotine by UV spectroscopy, high-resolution mass spectrometry, nuclear magnetic resonance, and Fourier transform-infrared spectroscopy analyses. The two-component nicotine dehydrogenase genes nctA1 and nctA2 were cloned, and their product, NctA, was confirmed to be responsible for the conversion of nornicotine into 6-hydroxy-nornicotine as well as nicotine into 6-hydroxy-nicotine. The 6-hydroxy-nicotine oxidase, NctB, catalyzed the oxidation of 6-hydroxy-nornicotine to 6-hydroxy-myosmine, and it spontaneously hydrolyzed into 6-hydroxy-pseudooxy-nornicotine. However, 6-hydroxy-pseudooxy-nornicotine could not be further degraded by strain HZN7. This study demonstrated that nornicotine is partially transformed by strain HZN7 via nicotine degradation pathway.