RosR (Cg1324), a hydrogen peroxide-sensitive MarR-type transcriptional regulator of Corynebacterium glutamicum.
The cg1324 gene (rosR) of Corynebacterium glutamicum encodes a MarR-type transcriptional regulator. By a comparative transcriptome analysis with DNA microarrays of a ΔrosR mutant and the wild type and subsequent EMSAs with purified RosR protein, direct target genes of RosR were identified. The narKGHJI operon, which encodes a nitrate/nitrite transporter and the dissimilatory nitrate reductase complex, was activated by RosR. All other target genes were repressed by RosR. They encode four putative monooxygenases, two putative FMN reductases, a protein of the glutathione S-transferase family, a putative polyisoprenoid-binding protein, and RosR itself. The DNA binding site of RosR was characterized as an 18-bp inverted repeat with the consensus sequence TTGTTGAYRYRTCAACWA. The in vitro DNA binding activity of RosR was reversibly inhibited by the oxidant H(2)O(2). Mutational analysis of the three cysteine residues present in RosR (Cys-64, Cys-92, and Cys-151) showed that these are responsible for the inhibition of DNA binding by H(2)O(2). A deletion mutant (Δcg1322) lacking the putative polyisoprenoid-binding protein showed an increased sensitivity to H(2)O(2), supporting the role of RosR in the oxidative stress response of C. glutamicum.
Bussmann
Michael
M
Institut für Biotechnologie 1, Forschungszentrum Jülich, D-52425 Jülich, Germany.
Baumgart
Meike
M
Bott
Michael
M
D020816:Amino Acid Motifs; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D002850:Chromatography, Gel; D048230:Corynebacterium glutamicum / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D024202:Electrophoretic Mobility Shift Assay; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects / Q000235:genetics; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D009154:Mutation; D021141:Nucleic Acid Amplification Techniques; D020411:Oligonucleotide Array Sequence Analysis; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D001426:Bacterial Proteins; D006861:Hydrogen Peroxide