Reductive dioxygen scavenging by flavo-diiron proteins of Clostridium acetobutylicum

• Published in: FEBS letters 2009-01, Vol.583 (1), p.241-245
• Main Authors: Hillmann, Falk, Riebe, Oliver, Fischer, Ralf-Jörg, Mot, Augustin, Caranto, Jonathan D., Kurtz, Donald M., Bahl, Hubert
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Clostridium acetobutylicum; Clostridium acetobutylicum - enzymology; Clostridium acetobutylicum - genetics; Dimerization; Escherichia coli; Escherichia coli - genetics; Flavo-diiron; Flavoproteins - chemistry; Flavoproteins - genetics; Flavoproteins - metabolism; Molecular Sequence Data; NADH, NADPH Oxidoreductases - chemistry; NADH, NADPH Oxidoreductases - genetics; NADH, NADPH Oxidoreductases - metabolism; Nitric Oxide - chemistry; Nitric Oxide - metabolism; O2 reduction; Oxidation-Reduction; Oxygen - chemistry; Oxygen - metabolism; Recombinant Proteins - chemistry; Recombinant Proteins - genetics; Recombinant Proteins - metabolism; Rubredoxin; Rubredoxins - genetics; Rubredoxins - metabolism
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/j.febslet.2008.12.004

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:O2 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.