title: Functioning of DcuC as the C4-dicarboxylate carrier during glucose fermentation by Escherichia coli.
abstract: The dcuC gene of Escherichia coli encodes an alternative C4-dicarboxylate carrier (DcuC) with low transport activity. The expression of dcuC was investigated. dcuC was expressed only under anaerobic conditions; nitrate and fumarate caused slight repression and stimulation of expression, respectively. Anaerobic induction depended mainly on the transcriptional regulator FNR. Fumarate stimulation was independent of the fumarate response regulator DcuR. The expression of dcuC was not significantly inhibited by glucose, assigning a role to DcuC during glucose fermentation. The inactivation of dcuC increased fumarate-succinate exchange and fumarate uptake by DcuA and DcuB, suggesting a preferential function of DcuC in succinate efflux during glucose fermentation. Upon overexpression in a dcuC promoter mutant (dcuC*), DcuC was able to compensate for DcuA and DcuB in fumarate-succinate exchange and fumarate uptake.
authors.affiliation: Institut für Mikrobiologie und Weinforschung, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Zientz
authors.forename: I G
authors.initials: IG
authors.lastname: Janausch
authors.forename: S
authors.initials: S
authors.lastname: Six
authors.forename: G
authors.initials: G
authors.lastname: Unden
mesh_terms: D000693:Anaerobiosis; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D016384:Consensus Sequence; D029382:Dicarboxylic Acid Transporters; D003998:Dicarboxylic Acids / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D029968:Escherichia coli Proteins; D005285:Fermentation; D005650:Fumarates / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005947:Glucose / Q000378:metabolism*; D007700:Kinetics; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D012270:Ribosomes / Q000378:metabolism; D013386:Succinates / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; C102904:DcuC protein, E coli; D029382:Dicarboxylic Acid Transporters; D003998:Dicarboxylic Acids; D029968:Escherichia coli Proteins; D005650:Fumarates; D013386:Succinates; D005947:Glucose