Previous studies have identified a putative mycothiol peroxidase (MPx) in Corynebacterium glutamicum that shared high sequence similarity to sulfur-containing Gpx (glutathione peroxidase; CysGPx). In the present study, we investigated the MPx function by examining its potential peroxidase activity using different proton donors. The MPx degrades hydrogen peroxide and alkyl hydroperoxides in the presence of either the thioredoxin/Trx reductase (Trx/TrxR) or the mycoredoxin 1/mycothione reductase/mycothiol (Mrx1/Mtr/MSH) regeneration system. Mrx1 and Trx employ different mechanisms in reducing MPx. For the Mrx1 system, the catalytic cycle of MPx involves mycothiolation/demycothiolation on the Cys36 sulfenic acid via the monothiol reaction mechanism. For the Trx system, the catalytic cycle of MPx involves formation of an intramolecular disulfide bond between Cys36 and Cys79 that is pivotal to the interaction with Trx. Both the Mrx1 pathway and the Trx pathway are operative in reducing MPx under stress conditions. Expression of mpx markedly enhanced the resistance to various peroxides and decreased protein carbonylation and intracellular reactive oxygen species (ROS) accumulation. The expression of mpx was directly activated by the stress-responsive extracytoplasmic function-σ (ECF-σ) factor [SigH]. Based on these findings, we propose that the C. glutamicum MPx represents a new type of GPx that uses both mycoredoxin and Trx systems for oxidative stress response.
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Research Article|
June 19 2015
Functional characterization of a mycothiol peroxidase in Corynebacterium glutamicum that uses both mycoredoxin and thioredoxin reducing systems in the response to oxidative stress
Meiru Si;
Meiru Si
*State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, PR China
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Yixiang Xu;
Yixiang Xu
*State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, PR China
†State Key Laboratory of Microbial Resources and Environmental Microbiology Research Center at Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China
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Tietao Wang;
Tietao Wang
*State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, PR China
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Mingxiu Long;
Mingxiu Long
‡College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, PR China
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Wei Ding;
Wei Ding
*State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, PR China
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Can Chen;
Can Chen
*State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, PR China
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Xinmeng Guan;
Xinmeng Guan
*State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, PR China
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Yingbao Liu;
Yingbao Liu
*State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, PR China
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Yao Wang;
Yao Wang
*State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, PR China
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Xihui Shen;
Xihui Shen
1
*State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, PR China
1To whom correspondence should be addressed (email xihuishen@nwsuaf.edu.cn).
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Shuang-Jiang Liu
Shuang-Jiang Liu
†State Key Laboratory of Microbial Resources and Environmental Microbiology Research Center at Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China
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Publisher: Portland Press Ltd
Received:
August 21 2014
Revision Received:
April 20 2015
Accepted:
April 20 2015
Accepted Manuscript online:
April 20 2015
Online ISSN: 1470-8728
Print ISSN: 0264-6021
© 2015 Authors; published by Portland Press Limited
2015
Biochem J (2015) 469 (1): 45–57.
Article history
Received:
August 21 2014
Revision Received:
April 20 2015
Accepted:
April 20 2015
Accepted Manuscript online:
April 20 2015
Citation
Meiru Si, Yixiang Xu, Tietao Wang, Mingxiu Long, Wei Ding, Can Chen, Xinmeng Guan, Yingbao Liu, Yao Wang, Xihui Shen, Shuang-Jiang Liu; Functional characterization of a mycothiol peroxidase in Corynebacterium glutamicum that uses both mycoredoxin and thioredoxin reducing systems in the response to oxidative stress. Biochem J 1 July 2015; 469 (1): 45–57. doi: https://doi.org/10.1042/BJ20141080
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