Archives of Microbiology

, Volume 190, Issue 6, pp 685–696

Biosynthesis of the respiratory formate dehydrogenases from Escherichia coli: characterization of the FdhE protein

  • Iris Lüke
  • Gareth Butland
  • Kevin Moore
  • Grant Buchanan
  • Verity Lyall
  • Shirley A. Fairhurst
  • Jack F. Greenblatt
  • Andrew Emili
  • Tracy Palmer
  • Frank Sargent
Original Paper

Abstract

Escherichia coli can perform two modes of formate metabolism. Under respiratory conditions, two periplasmically-located formate dehydrogenase isoenzymes couple formate oxidation to the generation of a transmembrane electrochemical gradient; and under fermentative conditions a third cytoplasmic isoenzyme is involved in the disproportionation of formate to CO2 and H2. The respiratory formate dehydrogenases are redox enzymes that comprise three subunits: a molybdenum cofactor- and FeS cluster-containing catalytic subunit; an electron-transferring ferredoxin; and a membrane-integral cytochrome b. The catalytic subunit and its ferredoxin partner are targeted to the periplasm as a complex by the twin-arginine transport (Tat) pathway. Biosynthesis of these enzymes is under control of an accessory protein termed FdhE. In this study, it is shown that E. coli FdhE interacts with the catalytic subunits of the respiratory formate dehydrogenases. Purification of recombinant FdhE demonstrates the protein is an iron-binding rubredoxin that can adopt monomeric and homodimeric forms. Bacterial two-hybrid analysis suggests the homodimer form of FdhE is stabilized by anaerobiosis. Site-directed mutagenesis shows that conserved cysteine motifs are essential for the physiological activity of the FdhE protein and are also involved in iron ligation.

Keywords

Bacterial respiration Formate dehydrogenase Enzyme biosynthesis Molecular chaperone 

Abbreviations

DMSO

Dimethyl sulphoxide

EPR

Electron paramagnetic resonance

SPA

Sequential peptide affinity

Tat

Twin-arginine translocation pathway

TMAO

Trimethylamine N-oxide

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  • Iris Lüke
    • 1
  • Gareth Butland
    • 2
    • 5
  • Kevin Moore
    • 3
  • Grant Buchanan
    • 1
  • Verity Lyall
    • 3
  • Shirley A. Fairhurst
    • 4
  • Jack F. Greenblatt
    • 2
  • Andrew Emili
    • 2
  • Tracy Palmer
    • 1
  • Frank Sargent
    • 1
  1. 1.Division of Molecular and Environmental Microbiology, College of Life SciencesUniversity of DundeeDundeeScotland, UK
  2. 2.Banting and Best Department of Medical Research, Terrence Donnelly Centre for Cellular and Biomedical ResearchUniversity of TorontoTorontoCanada
  3. 3.School of Biological SciencesUniversity of East AngliaNorwichUK
  4. 4.Department of Biological ChemistryJohn Innes CentreColneyUK
  5. 5.Life Sciences Division, Lawrence Berkeley National LaboratoryBerkeleyUSA

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