0000000000222295
AUTHOR
Andrea Ebert-jung
showing 5 related works from this author
Conversion of the sensor kinase DcuS ofEscherichia coliof the DcuB/DcuS sensor complex to the C4-dicarboxylate responsive form by the transporter DcuB
2016
Summary The sensor kinase DcuS of Escherichia coli co-operates under aerobic conditions with the C4-dicarboxylate transporter DctA to form the DctA/DcuS sensor complex. Under anaerobic conditions C4-dicarboxylate transport in fumarate respiration is catalyzed by C4-dicarboxylate/fumarate antiporter DcuB. (i) DcuB interacted with DcuS as demonstrated by a bacterial two-hybrid system (BACTH) and by co-chromatography of the solubilized membrane-proteins (mHPINE assay). (ii) In the DcuB/DcuS complex only DcuS served as the sensor since mutations in the substrate site of DcuS changed substrate specificity of sensing, and substrates maleate or 3-nitropropionate induced DcuS response without affec…
C4 ‐dicarboxylates and l ‐aspartate utilization by Escherichia coli K‐12 in the mouse intestine: l ‐aspartate as a major substrate for fumarate respi…
2021
C4-dicarboxylates, such as fumarate, L-malate and L-aspartate represent substrates for anaerobic growth of Escherichia coli by fumarate respiration. Here, we determined whether C4-dicarboxylate metabolism as well as fumarate respiration contribute to colonization of the mammalian intestinal tract. Metabolite profiling revealed that the murine small intestine contained high and low levels of L-aspartate and L-malate, respectively, whereas fumarate was nearly absent. Under laboratory conditions, addition of C4-dicarboxylate at concentrations corresponding to the levels of the C4-dicarboxylates in the small intestine (2.6 mMol/kg dry weight) induced the dcuBp-lacZ reporter gene (67% of maximal…
CitA/CitB Two-Component System Regulating Citrate Fermentation in Escherichia coli and Its Relation to the DcuS/DcuR System In Vivo
2011
ABSTRACT Citrate fermentation by Escherichia coli requires the function of the citrate/succinate antiporter CitT ( citT gene) and of citrate lyase ( citCDEFXG genes). Earlier experiments suggested that the two-component system CitA/CitB, consisting of the membrane-bound sensor kinase CitA and the response regulator CitB, stimulates the expression of the genes in the presence of citrate, similarly to CitA/CitB of Klebsiella pneumoniae . In this study, the expression of a chromosomal citC-lacZ gene fusion was shown to depend on CitA/CitB and citrate. CitA/CitB is related to the DcuS/DcuR two-component system which induces the expression of genes for fumarate respiration in response to C 4 -di…
Cellular Concentrations of the Transporters DctA and DcuB and the Sensor DcuS of Escherichia coli and the Contributions of Free and Complexed DcuS to…
2017
ABSTRACT In Escherichia coli , the catabolism of C 4 -dicarboxylates is regulated by the DcuS-DcuR two-component system. The functional state of the sensor kinase DcuS is controlled by C 4 -dicarboxylates (like fumarate) and complexation with the C 4 -dicarboxylate transporters DctA and DcuB, respectively. Free DcuS (DcuS F ) is known to be constantly active even in the absence of fumarate, whereas the DcuB-DcuS and DctA-DcuS complexes require fumarate for activation. To elucidate the impact of the transporters on the functional state of DcuS and the concentrations of DcuS F and DcuB-DcuS (or DctA-DcuS), the absolute levels of DcuS, DcuB, and DctA were determined in aerobically or anaerobic…
Glutathione metabolism and heavy metal detoxification in Schizosaccharomyces pombe
1991
Sixty glutathione-deficient mutants (gsh −) of Schizosaccharomyces pombe have been isolated by their resistance towards the mutagen N-methyl-N′-nitro-N-nitrosoguanidine (MNNG) and their sensitivity to the heavy metal Cadmium (Cd). fifty-three mutants show glutathione contents of less than 5% compared with the wild-type. The residual glutathione contents correlate with the resistance to MNNG, with the sensitivity to Cd and with the growth rate in minimal medium. The gsh −, Cd-sensitive (Cd s) mutants also show sensitivity to other heavy metals. Wild-type strains, but not the gsh − mutants, are able to excrete the heavy metal, very likely as a sulfide-containing compound. This inability of th…