Organization and transcriptional regulation of the Escherichia coli K-12 D-serine tolerance locus.
We have reinvestigated the genetic organization and the transcription regulation of the dsd operon of Escherichia coli. By combining genetic and biochemical studies, it is demonstrated that the regulatory region of the operon and the gene encoding the specific regulator of D-serine tolerance (dsdC) had been misplaced in previous work on the dsd system. Also, the previous erroneous DNA sequence of the dsdC gene has been corrected. It turned out that an additional gene (dsdX) is present immediately upstream of dsdA (encoding D-serine deaminase) and that dsdC is located adjacent to dsdX. The dsdXA genes are cotranscribed from a common promoter region present in the dsdX-dsdC intercistronic region. The DsdC activator belongs to the LysR-type of transcriptional regulators and is absolutely required for dsdA expression. Additionally, the activity of the dsdXA promoter depends on the cyclic AMP receptor protein, and the two activators act in concert to synergistically activate transcription.
Nørregaard-Madsen
M
M
Department of Molecular Biology, Odense University, Denmark.
McFall
E
E
Valentin-Hansen
P
P
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics*; D005798:Genes, Bacterial / Q000235:genetics; D012695:L-Serine Dehydratase / Q000235:genetics* / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D009876:Operon / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D012329:RNA, Bacterial / Q000096:biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D017422:Sequence Analysis, DNA; D012694:Serine / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics; D014158:Transcription, Genetic / Q000235:genetics*
D001426:Bacterial Proteins; C096747:DsdC protein, E coli; C096748:DsdX protein, E coli; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; D012329:RNA, Bacterial; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D012694:Serine; C104633:gluconate permease, E coli; C073470:LysR protein, Bacteria; D012695:L-Serine Dehydratase