0000000000363177
AUTHOR
Johannes Bongaerts
O2-sensing and O2-dependent gene regulation in facultatively anaerobic bacteria.
Availability of O2 is one of the most important regulatory signals in facultatively anaerobic bacteria. Various two- or one-component sensor/regulator systems control the expression of aerobic and anaerobic metabolism in response to O2. Most of the sensor proteins contain heme or Fe as cofactors that interact with O2 either by binding or by a redox reaction. The ArcA/ArcB regulator of aerobic metabolism in Escherichia coli may use a different sensory mechanism. In two-component regulators, the sensor is located in the cytoplasmic membrane, whereas one-component regulators are located in the cytoplasm. Under most conditions, O2 can readily reach the cytoplasm and could provide the signal in …
Growth phase-dependent regulation of nuoA-N expression in Escherichia coli K-12 by the Fis protein: upstream binding sites and bioenergetic significance.
The expression of the nuoA-N operon of Escherichia coli K-12, which encodes the proton-pumping NADH dehydrogenase I is modulated by growth phase-dependent regulation. Under respiratory growth conditions, expression was stimulated in early exponential, and to a lesser extent in late exponential and stationary growth phases. The stimulation in the early exponential growth phase was not observed in fis mutants, which are deficient for the growth phase-responsive regulator Fis. Neither the alternative sigma factor RpoS nor the integration host factor (IHF) are involved in growth phase-dependent regulation of this operon. When incubated with nuo promoter DNA, isolated Fis protein formed three re…
Fumarate regulation of gene expression in Escherichia coli by the DcuSR (dcuSR genes) two-component regulatory system.
ABSTRACT In Escherichia coli the genes encoding the anaerobic fumarate respiratory system are transcriptionally regulated by C 4 -dicarboxylates. The regulation is effected by a two-component regulatory system, DcuSR, consisting of a sensory histidine kinase (DcuS) and a response regulator (DcuR). DcuS and DcuR are encoded by the dcuSR genes (previously yjdHG ) at 93.7 min on the calculated E. coli map. Inactivation of the dcuR and dcuS genes caused the loss of C 4 -dicarboxylate-stimulated synthesis of fumarate reductase ( frdABCD genes) and of the anaerobic fumarate-succinate antiporter DcuB ( dcuB gene). DcuS is predicted to contain a large periplasmic domain as the supposed site for C 4…
Alternative respiratory pathways of Escherichia coli: energetics and transcriptional regulation in response to electron acceptors
AbstractThe electron-transport chains of Escherichia coli are composed of many different dehydrogenases and terminal reductases (or oxidases) which are linked by quinones (ubiquinone, menaquinone and demethylmenaquinone). Quinol:cytochrome c oxido-reductase (`bc1 complex') is not present. For various electron acceptors (O2, nitrate) and donors (formate, H2, NADH, glycerol-3-P) isoenzymes are present. The enzymes show great variability in membrane topology and energy conservation. Energy is conserved by conformational proton pumps, or by arrangement of substrate sites on opposite sides of the membrane resulting in charge separation. Depending on the enzymes and isoenzymes used, the H+/e− rat…
Transcriptional regulation of the proton translocating NADH dehydrogenase genes (nuoA-N) of Escherichia coli by electron acceptors, electron donors and gene regulators.
The promoter region and transcriptional regulation of the nuoA-N gene locus encoding the proton-translocating NADH:quinone oxidoreductase was analysed. A 560 bp intergenic region upstream of the nuo locus was followed by a gene (designated lrhA for LysR homologue A) coding for a gene regulator similar to those of the LysR family. Disruption of lrhA did not affect growth (respiratory or non-respiratory) or expression of nuo significantly. Transcriptional regulation of nuo by electron acceptors, electron donors and the transcriptional regulators ArcA, FNR, NarL and NarP, and by IHF (integration host factor) was studied with protein and operon fusions containing the promoter region up to base …
Requirement for the Proton-Pumping NADH Dehydrogenase I of Escherichia Coli in Respiration of NADH to Fumarate and Its Bioenergetic Implications
In Escherichia coli the expression of the nuo genes encoding the proton pumping NADH dehydrogenase I is stimulated by the presence of fumarate during anaerobic respiration. The regulatory sites required for the induction by fumarate, nitrate and O2 are located at positions around –309, –277, and downstream of –231 bp, respectively, relative to the transcriptional-start site. The fumarate regulator has to be different from the O2 and nitrate regulators ArcA and NarL. For growth by fumarate respiration, the presence of NADH dehydrogenase I was essential, in contrast to aerobic or nitrate respiration which used preferentially NADH dehydrogenase II. The electron transport from NADH to fumarate …
Oxygen regulated gene expression in facultatively anaerobic bacteria
In facultatively anaerobic bacteria such as Escherichia coli, oxygen and other electron acceptors fundamentally influence catabolic and anabolic pathways. E. coli is able to grow aerobically by respiration and in the absence of O2 by anaerobic respiration with nitrate, nitrite, fumarate, dimethylsulfoxide and trimethylamine N-oxide as acceptors or by fermentation. The expression of the various catabolic pathways occurs according to a hierarchy with 3 or 4 levels. Aerobic respiration at the highest level is followed by nitrate respiration (level 2), anaerobic respiration with the other acceptors (level 3) and fermentation. In other bacteria, different regulatory cascades with other underlyin…