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The role of thioredoxin TrxA in Bacillus subtilis : A proteomics and transcriptomics approach
Author(s) -
Mostertz Jörg,
Hochgräfe Falko,
Jürgen Britta,
Schweder Thomas,
Hecker Michael
Publication year - 2008
Publication title -
proteomics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.26
H-Index - 167
eISSN - 1615-9861
pISSN - 1615-9853
DOI - 10.1002/pmic.200701015
Subject(s) - bacillus subtilis , thioredoxin , biology , proteome , peroxiredoxin , biochemistry , proteomics , thiosulfate , gene expression , bacteria , microbiology and biotechnology , gene , sulfur , chemistry , enzyme , genetics , peroxidase , organic chemistry
Abstract Thiol‐disulfide oxidoreductases of the thioredoxin superfamily are crucial for maintaining the thiol redox state in living organisms. For the bacterium Bacillus subtilis thioredoxin A (TrxA) was described as the product of an essential gene indicating a key role during growth. By means of mRNA profiling Smits et al. ( J. Bacteriol. 2005, 187 , 3921–3930) suggested a critical function for TrxA in sulfur utilization during stationary phase. We extended the analysis of TrxA to exponential growth and characterized a trxA conditional mutant by proteome analysis complemented by transcriptomics. After TrxA‐depletion, the growth rate was dramatically decreased. The cells responded at mRNA and protein level by the increased expression of genes involved in the utilization of sulfur, which represents the most obvious response as visualized by gel‐based proteomics. Furthermore, several genes of the antioxidant response were found at higher expression levels after TrxA‐depletion. When sulfate was replaced by thiosulfate or methionine as sulfur source, the growth inhibition was abolished. In the presence of thiosulfate but in the absence of TrxA, the induction of the sulfur limitation response and the oxidative stress response was not observed. Our results show that the global change of gene expression is primarily caused by the interruption of the sulfate utilization after TrxA depletion. Thus, its function in sulfate assimilation renders TrxA an essential protein in growing B. subtilis cells.