title: Reductive dioxygen scavenging by flavo-diiron proteins of Clostridium acetobutylicum.
abstract: Two flavo-diiron proteins (FDPs), FprA1 and FprA2, are up-regulated when the strictly anaerobic solvent producer, Clostridium acetobutylicum, is exposed to dioxygen. These two FDPs were purified following heterologous overexpression in Escherichia coli as N-terminal Strep-tag fusion proteins. The recombinant FprA1 and FprA2 were found to be homodimeric and homotetrameric, respectively, and both FDPs functioned as terminal components of NADH oxidases (NADH:O(2) oxidoreductases) when using C. acetobutylicum NADH:rubredoxin oxidoreductase (NROR) and rubredoxin (Rd) as electron transport intermediaries. Both FDPs catalyzed the four-electron reduction of molecular oxygen to water with similar specific activities. The results are consistent with these FDPs functioning as efficient scavengers of intracellular dioxygen under aerobic or microoxic growth conditions.
authors.affiliation: Division of Microbiology, Institute of Biological Sciences, University of Rostock, Rostock, Germany.
authors.forename: Falk
authors.initials: F
authors.lastname: Hillmann
authors.forename: Oliver
authors.initials: O
authors.lastname: Riebe
authors.forename: Ralf-Jörg
authors.initials: RJ
authors.lastname: Fischer
authors.forename: Augustin
authors.initials: A
authors.lastname: Mot
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Caranto
authors.forename: Donald M
authors.initials: DM
authors.lastname: Kurtz
authors.forename: Hubert
authors.initials: H
authors.lastname: Bahl
mesh_terms: D000595:Amino Acid Sequence; D046969:Clostridium acetobutylicum / Q000201:enzymology* / Q000235:genetics; D019281:Dimerization; D004926:Escherichia coli / Q000235:genetics; D005420:Flavoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009247:NADH, NADPH Oxidoreductases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009569:Nitric Oxide / Q000737:chemistry / Q000378:metabolism; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012416:Rubredoxins / Q000235:genetics / Q000378:metabolism
chemical_list: D005420:Flavoproteins; D011994:Recombinant Proteins; D012416:Rubredoxins; D009569:Nitric Oxide; C023091:rubredoxin-NAD+ reductase; D009247:NADH, NADPH Oxidoreductases; D010100:Oxygen