Regulation of tartrate metabolism by TtdR and relation to the DcuS-DcuR-regulated C4-dicarboxylate metabolism of Escherichia coli.
Escherichia coli catabolizes L-tartrate under anaerobic conditions to oxaloacetate by the use of L-tartrate/succinate antiporter TtdT and L-tartrate dehydratase TtdAB. Subsequently, L-malate is channelled into fumarate respiration and degraded to succinate by the use of fumarase FumB and fumarate reductase FrdABCD. The genes encoding the latter pathway (dcuB, fumB and frdABCD) are transcriptionally activated by the DcuS-DcuR two-component system. Expression of the L-tartrate-specific ttdABT operon encoding TtdAB and TtdT was stimulated by the LysR-type gene regulator TtdR in the presence of L- and meso-tartrate, and repressed by O(2) and nitrate. Anaerobic expression required a functional fnr gene, and nitrate repression depended on NarL and NarP. Expression of ttdR, encoding TtdR, was repressed by O(2), nitrate and glucose, and positively regulated by TtdR and DcuS. Purified TtdR specifically bound to the ttdR-ttdA promoter region. TtdR was also required for full expression of the DcuS-DcuR-dependent dcuB gene in the presence of tartrate. Overall, expression of the ttdABT genes is subject to L-/meso-tartrate-dependent induction, and to aerobic and nitrate repression. The control is exerted directly at ttdA and in addition indirectly by regulating TtdR levels. TtdR recognizes a subgroup (L- and meso-tartrate) of the stimuli perceived by the sensor DcuS, which responds to all C(4)-dicarboxylates; both systems apparently communicate by mutual regulation of the regulatory genes.
Kim
Ok Bin
OB
Institut für Mikrobiologie und Weinforschung, Johannes Gutenberg-Universität Mainz, Becherweg 15, 55099 Mainz, Germany.
Reimann
Julia
J
Institut für Mikrobiologie und Weinforschung, Johannes Gutenberg-Universität Mainz, Becherweg 15, 55099 Mainz, Germany.
Lukas
Hanna
H
Institut für Mikrobiologie und Weinforschung, Johannes Gutenberg-Universität Mainz, Becherweg 15, 55099 Mainz, Germany.
Schumacher
Uwe
U
Institut für Mikrobiologie und Weinforschung, Johannes Gutenberg-Universität Mainz, Becherweg 15, 55099 Mainz, Germany.
Grimpo
Jan
J
Institut für Mikrobiologie und Weinforschung, Johannes Gutenberg-Universität Mainz, Becherweg 15, 55099 Mainz, Germany.
Dünnwald
Pia
P
Institut für Mikrobiologie und Weinforschung, Johannes Gutenberg-Universität Mainz, Becherweg 15, 55099 Mainz, Germany.
Unden
Gottfried
G
Institut für Mikrobiologie und Weinforschung, Johannes Gutenberg-Universität Mainz, Becherweg 15, 55099 Mainz, Germany.
D017920:Antiporters / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D005947:Glucose / Q000378:metabolism; D006836:Hydro-Lyases / Q000235:genetics / Q000378:metabolism*; D009566:Nitrates / Q000378:metabolism; D009876:Operon; D010100:Oxygen / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011494:Protein Kinases / Q000378:metabolism; D013379:Substrate Specificity; D013644:Tartrates / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism
D017920:Antiporters; D004268:DNA-Binding Proteins; C115005:DcuR protein, E coli; D029968:Escherichia coli Proteins; D009566:Nitrates; D013644:Tartrates; D014157:Transcription Factors; D011494:Protein Kinases; C469359:DcuS protein, E coli; D006836:Hydro-Lyases; C083087:L(+)-tartrate dehydratase; D005947:Glucose; D010100:Oxygen; C029768:tartaric acid