title: The flavoprotein FerB of Paracoccus denitrificans binds to membranes, reduces ubiquinone and superoxide, and acts as an in vivo antioxidant.
abstract: FerB is a flavin mononucleotide (FMN)-containing
  acceptor oxidoreductase of unknown function that is found in the cytoplasm of the bacterium Paracoccus denitrificans. Based on measurements of fluorescence anisotropy, we report here that recombinant FerB readily binds to artificial membrane vesicles. If ubiquinone is incorporated into the membrane, FerB catalyzes its conversion to ubihydroquinone, which may be followed fluorimetrically (with ferricyanide and pyranine entrapped inside the liposomes) or by HPLC. FerB also reduces exogenously added superoxide or superoxide that has been enzymatically generated by the xanthine/xanthine oxidase system or P. denitrificans membrane vesicles. In whole cells, deficiency of FerB increases sensitivity to methyl viologen, as indicated by a lower growth rate and increased production of reactive aldehydes (by-products of lipid oxidation). Taken together, these data support a role for FerB in protection of cells against lipid peroxidation-mediated oxidative stress, and suggest that FerB is a prokaryotic counterpart of mammalian
  quinone oxidoreductase 1.
authors.affiliation: Department of Biochemistry, Faculty of Science, Masaryk University, Brno, Czech Republic.
authors.forename: Vojtĕch
authors.initials: V
authors.lastname: Sedláček
authors.forename: Nikola
authors.initials: N
authors.lastname: Ptáčková
authors.forename: Petra
authors.initials: P
authors.lastname: Rejmontová
authors.forename: Igor
authors.initials: I
authors.lastname: Kučera
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000737:chemistry / Q000378:metabolism*; D005420:Flavoproteins / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D010231:Paracoccus denitrificans / Q000201:enzymology; D013481:Superoxides / Q000378:metabolism; D014451:Ubiquinone / Q000378:metabolism; D019820:Xanthine / Q000378:metabolism; D014969:Xanthine Oxidase / Q000378:metabolism
chemical_list: D000975:Antioxidants; D005420:Flavoproteins; D008565:Membrane Proteins; D013481:Superoxides; D014451:Ubiquinone; D019820:Xanthine; D014969:Xanthine Oxidase
keywords: Paracoccus denitrificans; flavoprotein; oxidative stress; superoxide; ubiquinone