title: C4-dicarboxylate carriers and sensors in bacteria.
abstract: Bacteria contain secondary carriers for the uptake, exchange or efflux of C4-dicarboxylates. In aerobic bacteria, dicarboxylate transport (Dct)A carriers catalyze uptake of C4-dicarboxylates in a H(+)- or Na(+)-C4-dicarboxylate symport. Carriers of the dicarboxylate uptake (Dcu)AB family are used for electroneutral fumarate:succinate antiport which is required in anaerobic fumarate respiration. The DcuC carriers apparently function in succinate efflux during fermentation. The tripartite ATP-independent periplasmic (TRAP) transporter carriers are secondary uptake carriers requiring a periplasmic solute binding protein. For heterologous exchange of C4-dicarboxylates with other carboxylic acids (such as citrate:succinate by CitT) further types of carriers are used. The different families of C4-dicarboxylate carriers, the biochemistry of the transport reactions, and their metabolic functions are described. Many bacteria contain membraneous C4-dicarboxylate sensors which control the synthesis of enzymes for C4-dicarboxylate metabolism. The C4-dicarboxylate sensors DcuS, DctB, and DctS are histidine protein kinases and belong to different families of two-component systems. They contain periplasmic domains presumably involved in C4-dicarboxylate sensing. In DcuS the periplasmic domain seems to be essential for direct interaction with the C4-dicarboxylates. In signal perception by DctB, interaction of the C4-dicarboxylates with DctB and the DctA carrier plays an important role.
authors.affiliation: Institut für Mikrobiologie und Weinforschung, Johann Gutenberg-Universität Mainz, Germany.
authors.forename: I G
authors.initials: IG
authors.lastname: Janausch
authors.forename: E
authors.initials: E
authors.lastname: Zientz
authors.forename: Q H
authors.initials: QH
authors.lastname: Tran
authors.forename: A
authors.initials: A
authors.lastname: Kröger
authors.forename: G
authors.initials: G
authors.lastname: Unden
mesh_terms: D000595:Amino Acid Sequence; D001420:Bacteria, Aerobic / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D001692:Biological Transport; D029382:Dicarboxylic Acid Transporters / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism; D029968:Escherichia coli Proteins; D005650:Fumarates / Q000378:metabolism; D008956:Models, Chemical; D027361:Organic Anion Transporters / Q000378:metabolism*; D010802:Phylogeny; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D019802:Succinic Acid / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; C113956:CitT protein, E coli; D029382:Dicarboxylic Acid Transporters; D029968:Escherichia coli Proteins; D005650:Fumarates; D027361:Organic Anion Transporters; D011956:Receptors, Cell Surface; C073787:DCTB protein, Sinorhizobium; C032005:fumaric acid; D019802:Succinic Acid; D011494:Protein Kinases