Positive transcriptional control of the pyridoxal phosphate biosynthesis genes pdxST by the MocR-type regulator PdxR of Corynebacterium glutamicum ATCC 13032.
The pdxR (cg0897) gene of Corynebacterium glutamicum ATCC 13032 encodes a regulatory protein belonging to the MocR subfamily of GntR-type transcription regulators and consisting of an amino-terminal winged helix-turn-helix DNA-binding domain and a carboxy-terminal aminotransferase-like domain. A defined deletion in the pdxR gene resulted in the decreased expression of the divergently orientated pdxST genes coding for the subunits of pyridoxal 5'-phosphate synthase. The pdxST mutant C. glutamicum NJ0898 and the pdxR mutant C. glutamicum AMH17 showed vitamin B(6) auxotrophy that was restored by supplementing the growth medium with either pyridoxal, pyridoxal 5'-phosphate or pyridoxamine. The genetic organization of the 89 bp pdxR-pdxST intergenic region was elucidated by mapping the 5' ends of the respective transcripts, followed by detection of typical promoter sequences. Bioinformatic pattern searches and comparative genomics revealed three DNA motifs with the consensus sequence AAAGTGGW(-/T)CTA, overlapping the deduced promoter sequences and serving as candidate DNA-binding sites for PdxR. DNA band shift assays with the purified PdxR protein demonstrated the specific binding of the transcription regulator to double-stranded 40-mer sequences containing the detected motifs, thereby confirming the direct regulatory role of PdxR in activating the expression of the pdxST genes.
Jochmann
Nina
N
International NRW Graduate School in Bioinformatics and Genome Research, Centrum für Biotechnologie, Universität Bielefeld, Universitätsstraße 25, D-33615 Bielefeld, Germany.|Institut für Genomforschung und Systembiologie, Centrum für Biotechnologie, Universität Bielefeld, Universitätsstraße 27, D-33615 Bielefeld, Germany.
Götker
Susanne
S
Institut für Genomforschung und Systembiologie, Centrum für Biotechnologie, Universität Bielefeld, Universitätsstraße 27, D-33615 Bielefeld, Germany.
Tauch
Andreas
A
Institut für Genomforschung und Systembiologie, Centrum für Biotechnologie, Universität Bielefeld, Universitätsstraße 27, D-33615 Bielefeld, Germany.
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites; D048230:Corynebacterium glutamicum / Q000235:genetics* / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D021901:DNA, Intergenic; D024202:Electrophoretic Mobility Shift Assay; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D011730:Pyridoxal / Q000378:metabolism; D011732:Pyridoxal Phosphate / Q000096:biosynthesis*; D011733:Pyridoxamine / Q000378:metabolism; D016415:Sequence Alignment; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D024363:Transcription Initiation Site; D025101:Vitamin B 6 / Q000096:biosynthesis
D001426:Bacterial Proteins; D003470:Culture Media; D004269:DNA, Bacterial; D021901:DNA, Intergenic; D015534:Trans-Activators; D011730:Pyridoxal; D011732:Pyridoxal Phosphate; D011733:Pyridoxamine; D025101:Vitamin B 6