- 著者
- Shun Kobayashi Daisuke Hira Keitaro Yoshida Masanori Toyofuku Yosuke Shida Wataru Ogasawara Takashi Yamaguchi Nobuo Araki Mamoru Oshiki
- 出版者
- Japanese Society of Microbial Ecology · The Japanese Society of Soil Microbiology
- 雑誌
- Microbes and Environments (ISSN:13426311)
- 巻号頁・発行日
- pp.ME18058, (Released:2018-10-12)
- 被引用文献数
- 35
Aerobic ammonia-oxidizing archaea (AOA) play a crucial role in the global nitrogen cycle by oxidizing ammonia to nitrite, and nitric oxide (NO) is a key intermediate in AOA for sustaining aerobic ammonia oxidation activity. We herein heterologously expressed the NO-forming, copper-containing, dissimilatory nitrite reductase (NirK) from Nitrososphaera viennensis and investigated its enzymatic properties. The recombinant protein catalyzed the reduction of 15NO2– to 15NO, the oxidation of hydroxylamine (15NH2OH) to 15NO, and the production of 14-15N2O from 15NH2OH and 14NO2–. To the best of our knowledge, the present study is the first to document the enzymatic properties of AOA NirK.
- 著者
- Kentaro Suzuki Mari Michikawa Haruna Sato Masahiro Yuki Kei Kamino Wataru Ogasawara Shinya Fushinobu Satoshi Kaneko
- 出版者
- The Japanese Society of Applied Glycoscience
- 雑誌
- Journal of Applied Glycoscience (ISSN:13447882)
- 巻号頁・発行日
- vol.65, no.2, pp.13-21, 2018-05-20 (Released:2018-05-20)
- 参考文献数
- 40
- 被引用文献数
- 9
Highly thermostable β-mannanase, belonging to glycoside hydrolase family 5 subfamily 7, was purified from the culture supernatant of Talaromyces trachyspermus B168 and the cDNA of its transcript was cloned. The recombinant enzyme showed maximal activity at pH 4.5 and 85 °C. It retained more than 90 % of its activity below 60 °C. Obtaining the crystal structure of the enzyme helped us to understand the mechanism of its thermostability. An antiparallel β-sheet, salt-bridges, hydrophobic packing, proline residues in the loops, and loop shortening are considered to be related to the thermostability of the enzyme. The enzyme hydrolyzed mannans such as locust bean gum, carob galactomannan, guar gum, konjac glucomannan, and ivory nut mannan. It hydrolyzed 50.7 % of the total mannans from coffee waste, producing mannooligosaccharides. The enzyme has the highest optimum temperature among the known fungal β-mannanases and has potential for use in industrial applications.
- 著者
- Shun Kobayashi Daisuke Hira Keitaro Yoshida Masanori Toyofuku Yosuke Shida Wataru Ogasawara Takashi Yamaguchi Nobuo Araki Mamoru Oshiki
- 出版者
- Japanese Society of Microbial Ecology · The Japanese Society of Soil Microbiology
- 雑誌
- Microbes and Environments (ISSN:13426311)
- 巻号頁・発行日
- vol.33, no.4, pp.428-434, 2018 (Released:2018-12-28)
- 参考文献数
- 47
- 被引用文献数
- 1 35
Aerobic ammonia-oxidizing archaea (AOA) play a crucial role in the global nitrogen cycle by oxidizing ammonia to nitrite, and nitric oxide (NO) is a key intermediate in AOA for sustaining aerobic ammonia oxidation activity. We herein heterologously expressed the NO-forming, copper-containing, dissimilatory nitrite reductase (NirK) from Nitrososphaera viennensis and investigated its enzymatic properties. The recombinant protein catalyzed the reduction of 15NO2− to 15NO, the oxidation of hydroxylamine (15NH2OH) to 15NO, and the production of 14–15N2O from 15NH2OH and 14NO2−. To the best of our knowledge, the present study is the first to document the enzymatic properties of AOA NirK.
- 著者
- Hitomi Ichinose Kentaro Suzuki Mari Michikawa Haruna Sato Masahiro Yuki Kei Kamino Wataru Ogasawara Shinya Fushinobu Satoshi Kaneko
- 出版者
- The Japanese Society of Applied Glycoscience
- 雑誌
- Journal of Applied Glycoscience (ISSN:13447882)
- 巻号頁・発行日
- pp.jag.JAG-2017_018, (Released:2017-12-29)
- 被引用文献数
- 9
Highly thermostable β-mannanase, belonging to glycoside hydrolase family 5 subfamily 7, was purified from the culture supernatant of Talaromyces trachyspermus B168 and the cDNA of its transcript was cloned. The recombinant enzyme showed maximal activity at pH 4.5 and 85 °C. It retained more than 90 % of its activity below 60 °C. Obtaining the crystal structure of the enzyme helped us to understand the mechanism of its thermostability. An antiparallel β-sheet, salt-bridges, hydrophobic packing, proline residues in the loops, and loop shortening are considered to be related to the thermostability of the enzyme. The enzyme hydrolyzed mannans such as locust bean gum, carob galactomannan, guar gum, konjac glucomannan, and ivory nut mannan. It hydrolyzed 50.7 % of the total mannans from coffee waste, producing mannooligosaccharides. The enzyme has the highest optimum temperature among the known fungal β-mannanases and has potential for use in industrial applications.