title: Sequence analysis and interposon mutagenesis of a sensor-kinase (DctS) and response-regulator (DctR) controlling synthesis of the high-affinity C4-dicarboxylate transport system in Rhodobacter capsulatus.
abstract: A two-component sensor-regulator system has been identified in the purple photosynthetic bacterium Rhodobacter capsulatus, which controls the expression of high-affinity C4-dicarboxylate transport activity in these cells. Nucleotide sequencing has revealed the existence of two genes, dctS and dctR, which together form an operon linked to, but divergently transcribed from, the previously identified dctP gene, which encodes the periplasmic binding protein of the transport system. The DctS protein is predicted to be a membrane-bound sensor-kinase with two potential membrane-spanning sequences in the N-terminal region. DctR was found to have sequence similarity throughout its entire length with proteins in the FixJ subfamily of response-regulators, especially to FixJ itself (42% identical residues). Insertional inactivation of the dctS and dctR genes resulted in the inability of the resulting mutants to grow on or transport malate, succinate or fumarate under aerobic conditions in the dark, and such mutants did not express the DctP protein. The mutants were complemented in trans by plasmids containing intact copies of the dctS and dctR genes.
authors.affiliation: Krebs and Robert Hill Institutes, Department of Molecular Biology and Biotechnology, University of Sheffield, U.K.
authors.forename: M J
authors.initials: MJ
authors.lastname: Hamblin
authors.forename: J G
authors.initials: JG
authors.lastname: Shaw
authors.forename: D J
authors.initials: DJ
authors.lastname: Kelly
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D001692:Biological Transport; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D003998:Dicarboxylic Acids / Q000378:metabolism*; D005650:Fumarates / Q000378:metabolism; D000071677:Histidine Kinase; D008293:Malates / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D009876:Operon; D017433:Protein Structure, Secondary; D011773:Pyruvates / Q000378:metabolism; D015183:Restriction Mapping; D016354:Rhodobacter capsulatus / Q000235:genetics* / Q000378:metabolism*; D016415:Sequence Alignment; D017421:Sequence Analysis; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D013386:Succinates / Q000378:metabolism; D019802:Succinic Acid; D014157:Transcription Factors
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; C080282:DctR protein, Rhodobacter capsulatus; D003998:Dicarboxylic Acids; D005650:Fumarates; D008293:Malates; D008565:Membrane Proteins; D011773:Pyruvates; D013386:Succinates; D014157:Transcription Factors; C069289:FixJ protein, Bacteria; C032005:fumaric acid; D019802:Succinic Acid; C080283:DctS protein, Rhodobacter capsulatus; D000071677:Histidine Kinase