title: Effects of the deletion of the Escherichia coli frataxin homologue CyaY on the respiratory NADH:ubiquinone oxidoreductase.
abstract: BACKGROUND
  Frataxin is discussed as involved in the biogenesis of iron-sulfur clusters. Recently it was discovered that a frataxin homologue is a structural component of the respiratory NADH:ubiquinone oxidoreductase (complex I) in Thermus thermophilus. It was not clear whether frataxin is in general a component of complex I from bacteria. The Escherichia coli homologue of frataxin is coined CyaY.
  
  
  RESULTS
  We report that complex I is completely assembled to a stable and active enzyme complex equipped with all known iron-sulfur clusters in a cyaY mutant of E. coli. However, the amount of complex I is reduced by one third compared to the parental strain. Western blot analysis and live cell imaging of CyaY engineered with a GFP demonstrated that CyaY is located in the cytoplasm and not attached to the membrane as to be expected if it were a component of complex I.
  
  
  CONCLUSIONS
  CyaY plays a non-essential role in the assembly of complex I in E. coli. It is not a structural component but may transiently interact with the complex.
authors.affiliation: Institute of Organic Chemistry and Biochemistry, University of Freiburg, Freiburg, Germany. tpohl@uni-freiburg.de <tpohl@uni-freiburg.de>
authors.forename: Thomas
authors.initials: T
authors.lastname: Pohl
authors.forename: Julia
authors.initials: J
authors.lastname: Walter
authors.forename: Stefan
authors.initials: S
authors.lastname: Stolpe
authors.forename: Joel H Defeu
authors.initials: JH
authors.lastname: Soufo
authors.forename: Peter L
authors.initials: PL
authors.lastname: Grauman
authors.forename: Thorsten
authors.initials: T
authors.lastname: Friedrich
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002384:Catalysis; D002462:Cell Membrane / Q000201:enzymology; D003593:Cytoplasm / Q000201:enzymology; D004578:Electron Spin Resonance Spectroscopy; D004926:Escherichia coli / Q000166:cytology / Q000201:enzymology* / Q000235:genetics; D029968:Escherichia coli Proteins; D017353:Gene Deletion; D033862:Iron-Binding Proteins / Q000737:chemistry*; D050296:Microbial Viability; D009243:NAD / Q000378:metabolism*; D010088:Oxidoreductases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D010101:Oxygen Consumption; D011485:Protein Binding; D014451:Ubiquinone / Q000378:metabolism*; D000096923:Frataxin
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D033862:Iron-Binding Proteins; D009243:NAD; D010088:Oxidoreductases; D014451:Ubiquinone; D000096923:Frataxin; C120906:CyaY protein, E coli