title: Impact of global transcriptional regulation by ArcA, ArcB, Cra, Crp, Cya, Fnr, and Mlc on glucose catabolism in Escherichia coli.
abstract: Even though transcriptional regulation plays a key role in establishing the metabolic network, the extent to which it actually controls the in vivo distribution of metabolic fluxes through different pathways is essentially unknown. Based on metabolism-wide quantification of intracellular fluxes, we systematically elucidated the relevance of global transcriptional regulation by ArcA, ArcB, Cra, Crp, Cya, Fnr, and Mlc for aerobic glucose catabolism in batch cultures of Escherichia coli. Knockouts of ArcB, Cra, Fnr, and Mlc were phenotypically silent, while deletion of the catabolite repression regulators Crp and Cya resulted in a pronounced slow-growth phenotype but had only a nonspecific effect on the actual flux distribution. Knockout of ArcA-dependent redox regulation, however, increased the aerobic tricarboxylic acid (TCA) cycle activity by over 60%. Like aerobic conditions, anaerobic derepression of TCA cycle enzymes in an ArcA mutant significantly increased the in vivo TCA flux when nitrate was present as an electron acceptor. The in vivo and in vitro data demonstrate that ArcA-dependent transcriptional regulation directly or indirectly controls TCA cycle flux in both aerobic and anaerobic glucose batch cultures of E. coli. This control goes well beyond the previously known ArcA-dependent regulation of the TCA cycle during microaerobiosis.
authors.affiliation: Institute of Biotechnology, ETH Zürich, CH-8093 Zürich, Switzerland.
authors.forename: Annik
authors.initials: A
authors.lastname: Perrenoud
authors.forename: Uwe
authors.initials: U
authors.lastname: Sauer
mesh_terms: D000693:Anaerobiosis; D001425:Bacterial Outer Membrane Proteins / Q000502:physiology; D001426:Bacterial Proteins / Q000502:physiology; D002952:Citric Acid Cycle / Q000502:physiology; D002373:Cyclic AMP Receptor Protein; D004734:Energy Metabolism; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000502:physiology*; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D005947:Glucose / Q000378:metabolism*; D007506:Iron-Sulfur Proteins / Q000502:physiology; D008565:Membrane Proteins / Q000502:physiology; D016254:Mutagenesis, Insertional; D009566:Nitrates / Q000378:metabolism; D010084:Oxidation-Reduction; D011494:Protein Kinases / Q000502:physiology; D011956:Receptors, Cell Surface / Q000502:physiology; D012097:Repressor Proteins / Q000502:physiology; D014157:Transcription Factors / Q000502:physiology; D014158:Transcription, Genetic; D056968:Lac Repressors
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002373:Cyclic AMP Receptor Protein; D029968:Escherichia coli Proteins; D005947:Glucose; D007506:Iron-Sulfur Proteins; D008565:Membrane Proteins; D009566:Nitrates; D011494:Protein Kinases; D011956:Receptors, Cell Surface; D012097:Repressor Proteins; D014157:Transcription Factors; C060704:FNR protein, E coli; C111065:Mlc protein, E coli; C041610:arcA protein, E coli; C481662:crp protein, E coli; C068837:FruR protein, Bacteria; D056968:Lac Repressors; C065271:arcB protein, E coli