title: Overexpression of Mycothiol Disulfide Reductase Enhances Corynebacterium glutamicum Robustness by Modulating Cellular Redox Homeostasis and Antioxidant Proteins under Oxidative Stress.
abstract: Mycothiol (MSH) is the dominant low-molecular-weight thiol (LMWT) unique to high-(G+C)-content Gram-positive Actinobacteria, such as Corynebacterium glutamicum, and is oxidised into its disulfide form mycothiol disulfide (MSSM) under oxidative conditions. Mycothiol disulfide reductase (Mtr), an NADPH-dependent enzyme, reduces MSSM to MSH, thus maintaining intracellular redox homeostasis. In this study, a recombinant plasmid was constructed to overexpress Mtr in C. glutamicum using the expression vector pXMJ19-His6. Mtr-overexpressing C. glutamicum cells showed increased tolerance to ROS induced by oxidants, bactericidal antibiotics, alkylating agents, and heavy metals. The physiological roles of Mtr in resistance to oxidative stresses were corroborated by decreased ROS levels, reduced carbonylation damage, decreased loss of reduced protein thiols, and a massive increase in the levels of reversible protein thiols in Mtr-overexpressing cells exposed to stressful conditions. Moreover, overexpression of Mtr caused a marked increase in the ratio of reduced to oxidised mycothiol (MSH:MSSM), and significantly enhanced the activities of a variety of antioxidant enzymes, including mycothiol peroxidase (MPx), mycoredoxin 1 (Mrx1), thioredoxin 1 (Trx1), and methionine sulfoxide reductase A (MsrA). Taken together, these results indicate that the Mtr protein functions in C. glutamicum by protecting cells against oxidative stress.
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China.|College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, China.|College of Life Sciences, Qufu Normal University, Qufu, Shandong 273165, China.
authors.forename: Meiru
authors.initials: M
authors.lastname: Si
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: Dawei
authors.initials: D
authors.lastname: Wei
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: Keqi
authors.initials: K
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: He
authors.initials: H
authors.lastname: Xiao
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: Xihui
authors.initials: X
authors.lastname: Shen
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D048230:Corynebacterium glutamicum / Q000201:enzymology / Q000235:genetics / Q000254:growth & development*; D003545:Cysteine / Q000378:metabolism; D006020:Glycopeptides / Q000378:metabolism; D006706:Homeostasis; D007294:Inositol / Q000378:metabolism; D009247:NADH, NADPH Oxidoreductases / Q000235:genetics* / Q000378:metabolism*; D010084:Oxidation-Reduction; D018384:Oxidative Stress
chemical_list: D001426:Bacterial Proteins; D006020:Glycopeptides; C089265:mycothiol; D007294:Inositol; D009247:NADH, NADPH Oxidoreductases; C089267:disulfide reductase, mycothiol; D003545:Cysteine