title: Characterization of CitA-CitB signal transduction activating genes involved in anaerobic citrate catabolism in Escherichia coli.
abstract: In Escherichia coli, CitA is a membrane-associated sensor histidine kinase that phosphorylates CitB, the response regulator. It is predicated to play a key role in anaerobic citrate catabolism. The citrate-binding site in CitA is located within its periplasmic domain, while the cytoplasmic domain (CitA-C) is involved in autophosphorylation. We found that autophosphorylation in vitro of CitA-C was induced by DTT. Using the whole set of CitA-C derivatives containing Cys-Ala substitution(s), Cys at 529 was found to be essential to the redox-sensing of autophosphorylation. The phosphorylated CitA-C transferred a phosphate to CitB. DNase-I footprinting assay indicated that CitB specifically bound on the intergenic region between the citA and citC genes. These results characterize the molecular mechanism of the CitA-CitB signal transduction system in E. coli.
authors.affiliation: Department of Frontier Bioscience and Research Center for Micro-Nano Technology, Hosei University, Koganei, Tokyo, Japan. kanyamam@hosei.ac.jp
authors.forename: Kaneyoshi
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Fumika
authors.initials: F
authors.lastname: Matsumoto
authors.forename: Shu
authors.initials: S
authors.lastname: Minagawa
authors.forename: Taku
authors.initials: T
authors.lastname: Oshima
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Fujita
authors.forename: Naotake
authors.initials: N
authors.lastname: Ogasawara
authors.forename: Akira
authors.initials: A
authors.lastname: Ishihama
mesh_terms: D000693:Anaerobiosis; D019343:Citric Acid / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D004926:Escherichia coli / Q000166:cytology / Q000235:genetics* / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism*; D005798:Genes, Bacterial; D010084:Oxidation-Reduction; D010766:Phosphorylation; D011494:Protein Kinases / Q000737:chemistry / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D015398:Signal Transduction / Q000235:genetics*; D013379:Substrate Specificity; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: C115181:CitB protein, E coli; D029968:Escherichia coli Proteins; D014157:Transcription Factors; D019343:Citric Acid; D011494:Protein Kinases; C460095:CitA protein, E coli