The RegB/RegA two-component regulatory system controls synthesis of photosynthesis and respiratory electron transfer components in Rhodobacter capsulatus

J Mol Biol. 2001 May 25;309(1):121-38. doi: 10.1006/jmbi.2001.4652.


Recently, we demonstrated that the RegB/RegA two-component regulatory system from Rhodobacter capsulatus functions as a global regulator of metabolic processes that either generate or consume reducing equivalents. For example, the RegB/RegA system controls expression of such energy generating processes as photosynthesis and hydrogen utilization. In addition, RegB/RegA also control nitrogen and carbon fixation pathways that utilize reducing equivalents. Here, we use a combination of DNase I protection and plasmid-based reporter expression studies to demonstrate that RegA directly controls synthesis of cytochrome cbb3 and ubiquinol oxidases that function as terminal electron acceptors in a branched respiratory chain. We also demonstrate that RegA controls expression of cytochromes c2, c(y) and the cytochrome bc1 complex that are involved in both photosynthetic and respiratory electron transfer events. These data provide evidence that the RegB/RegA two-component system has a major role in controlling the synthesis of numerous processes that affect reducing equivalents in Rhodobacter capsulatus.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Bacterial Proteins / metabolism*
  • Base Sequence
  • Binding Sites
  • Cytochrome c Group / biosynthesis
  • Cytochrome c Group / genetics
  • Cytochromes c2
  • DNA Footprinting
  • DNA, Bacterial / genetics
  • DNA, Bacterial / metabolism
  • DNA-Binding Proteins / metabolism
  • Deoxyribonuclease I / metabolism
  • Electron Transport / genetics*
  • Electron Transport Complex III / biosynthesis
  • Electron Transport Complex III / genetics
  • Electron Transport Complex IV / biosynthesis
  • Electron Transport Complex IV / genetics
  • Enzyme Induction
  • Gene Expression Regulation, Bacterial*
  • Genes, Bacterial / genetics
  • Genes, Reporter / genetics
  • Molecular Sequence Data
  • Photosynthesis / genetics*
  • Photosynthetic Reaction Center Complex Proteins / metabolism*
  • Promoter Regions, Genetic / genetics
  • Protein Kinases*
  • Quinone Reductases / biosynthesis
  • Quinone Reductases / genetics
  • RNA, Bacterial / genetics
  • RNA, Bacterial / metabolism
  • Rhodobacter capsulatus / enzymology
  • Rhodobacter capsulatus / genetics*
  • Rhodobacter capsulatus / metabolism
  • Sequence Alignment
  • Transcription Factors / metabolism


  • Bacterial Proteins
  • Cytochrome c Group
  • DNA, Bacterial
  • DNA-Binding Proteins
  • Photosynthetic Reaction Center Complex Proteins
  • RNA, Bacterial
  • RegA protein, Bacteria
  • RegB protein, Rhodobacter
  • Transcription Factors
  • cytochrome Cy
  • Cytochromes c2
  • Quinone Reductases
  • ubiquinol-1 oxidase
  • cbb3 oxidase
  • Electron Transport Complex IV
  • Protein Kinases
  • Deoxyribonuclease I
  • Electron Transport Complex III