Open AccessThe whcA gene plays a negative role in oxidative stress response of Corynebacterium glutamicum
Author(s) -
Choi WoonWoo,
Park SooDong,
Lee SeokMyung,
Kim HyungBai,
Kim Younhee,
Lee HeungShick
Publication year - 2009
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2008.01398.x
Subject(s) - corynebacterium glutamicum , mutant , biology , biochemistry , gene , menadione , thioredoxin reductase , microbiology and biotechnology , thioredoxin , oxidative stress
In this study, we analyzed the whcA gene from Corynebacterium glutamicum , which codes for a homologue of the WhiB‐family of proteins. Deletion of the gene did not affect the growth of the mutant cells, indicating that the whcA gene was not essential under ordinary growth conditions. However, cells overexpressing the protein not only showed retarded growth as compared with the wild‐type or the Δ whcA mutant cells but also showed increased sensitivity to a variety of oxidants, such as diamide, menadione, and hydrogen peroxide. Thioredoxin reductase activity was repressed in the whcA ‐overexpressing cells, whereas its activity in the Δ whcA mutant strain was derepressed regardless of the presence of oxidative stress. The whcA gene was constitutively expressed throughout the growth phase and its expression level was not affected by oxidative stress. A set of proteins under the control of whcA were identified by two‐dimensional polyacrylamide gel electrophoresis and they were annotated as NADH oxidase, alcohol dehydrogenase, quinone reductase, and cysteine desulfurase. The corresponding genes encoding the identified proteins were not transcribed in Δ sigH mutant cells. Collectively, these data suggest that the whcA gene of C. glutamicum plays a negative role in the sigH ‐mediated stress response pathway.