Characterization of CitA-CitB signal transduction activating genes involved in anaerobic citrate catabolism in Escherichia coli

Biosci Biotechnol Biochem. 2009 Feb;73(2):346-50. doi: 10.1271/bbb.80586. Epub 2009 Feb 7.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anaerobiosis
  • Citric Acid / metabolism*
  • Cytoplasm / metabolism
  • Escherichia coli / cytology
  • Escherichia coli / genetics*
  • Escherichia coli / metabolism*
  • Escherichia coli Proteins / chemistry
  • Escherichia coli Proteins / metabolism*
  • Genes, Bacterial*
  • Oxidation-Reduction
  • Phosphorylation
  • Protein Kinases / chemistry
  • Protein Kinases / metabolism*
  • Protein Structure, Tertiary
  • Signal Transduction / genetics*
  • Substrate Specificity
  • Transcription Factors / metabolism*

Substances

  • CitB protein, E coli
  • Escherichia coli Proteins
  • Transcription Factors
  • Citric Acid
  • Protein Kinases
  • CitA protein, E coli