caa a22 4500 605507244 CHVBK 20210128100631.0 cr unu---uuuuu 210128e20150401xx s 000 0 eng 10.1007/s00775-015-1248-4 doi (NATIONALLICENCE)springer-10.1007/s00775-015-1248-4 Dioxygen and nitric oxide scavenging by Treponema denticola flavodiiron protein: a mechanistic paradigm for catalysis [Elektronische Daten] [Rosanne Frederick, Jonathan Caranto, Cesar Masitas, Linda Gebhardt, Charles MacGowan, Ronald Limberger, Donald Kurtz Jr.] Flavodiiron proteins (FDPs) contain a unique active site consisting of a non-heme diiron carboxylate site proximal to a flavin mononucleotide (FMN). FDPs serve as the terminal components for reductive scavenging of dioxygen (to water) or nitric oxide (to nitrous oxide), which combats oxidative or nitrosative stress in many bacteria. Characterizations of FDPs from spirochetes or from any oral microbes have not been previously reported. Here, we report characterization of an FDP from the anaerobic spirochete, Treponema (T.) denticola, which is associated with chronic periodontitis. The isolated T. denticola FDP exhibited efficient four-electron dioxygen reductase activity and lower but significant anaerobic nitric oxide reductase activity. A mutant T. denticola strain containing the inactivated FDP-encoding gene was significantly more air-sensitive than the wild-type strain. Single turnover reactions of the four-electron-reduced FDP (FMNH2-FeIIFeII) (FDPred) with O2 monitored on the milliseconds to seconds time scale indicated initial rapid formation of a spectral feature consistent with a cis-μ-1,2-peroxo-diferric intermediate, which triggered two-electron oxidation of FMNH2. Reaction of FDPred with NO showed apparent cooperativity between binding of the first and second NO to the diferrous site. The resulting diferrous dinitrosyl complex triggered two-electron oxidation of the FMNH2. Our cumulative results on this and other FDPs indicate that smooth two-electron FMNH2 oxidation triggered by the FDPred/substrate complex and overall four-electron oxidation of FDPred to FDPox constitutes a mechanistic paradigm for both dioxygen and nitric oxide reductase activities of FDPs. Four-electron reductive O2 scavenging by FDPs could contribute to oxidative stress protection in many other oral bacteria. SBIC, 2015 Flavodiiron protein nationallicence Nitric oxide reductase nationallicence Dioxygen reductase nationallicence Spirochete nationallicence Treponema denticola nationallicence Frederick Rosanne Department of Chemistry, University of Texas at San Antonio, 78249, San Antonio, TX, USA aut Caranto Jonathan Department of Chemistry, University of Texas at San Antonio, 78249, San Antonio, TX, USA aut Masitas Cesar Department of Chemistry, University of Texas at San Antonio, 78249, San Antonio, TX, USA aut Gebhardt Linda Wadsworth Center, New York State Department of Health, 12201, Albany, NY, USA aut MacGowan Charles Wadsworth Center, New York State Department of Health, 12201, Albany, NY, USA aut Limberger Ronald Wadsworth Center, New York State Department of Health, 12201, Albany, NY, USA aut Kurtz Jr. Donald Department of Chemistry, University of Texas at San Antonio, 78249, San Antonio, TX, USA aut JBIC Journal of Biological Inorganic Chemistry Springer Berlin Heidelberg 20/3(2015-04-01), 603-613 0949-8257 20:3<603 2015 20 775 https://doi.org/10.1007/s00775-015-1248-4 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00775-015-1248-4 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Frederick Rosanne Department of Chemistry, University of Texas at San Antonio, 78249, San Antonio, TX, USA aut NATIONALLICENCE 700 1- Caranto Jonathan Department of Chemistry, University of Texas at San Antonio, 78249, San Antonio, TX, USA aut NATIONALLICENCE 700 1- Masitas Cesar Department of Chemistry, University of Texas at San Antonio, 78249, San Antonio, TX, USA aut NATIONALLICENCE 700 1- Gebhardt Linda Wadsworth Center, New York State Department of Health, 12201, Albany, NY, USA aut NATIONALLICENCE 700 1- MacGowan Charles Wadsworth Center, New York State Department of Health, 12201, Albany, NY, USA aut NATIONALLICENCE 700 1- Limberger Ronald Wadsworth Center, New York State Department of Health, 12201, Albany, NY, USA aut NATIONALLICENCE 700 1- Kurtz Jr Donald Department of Chemistry, University of Texas at San Antonio, 78249, San Antonio, TX, USA aut NATIONALLICENCE 773 0- JBIC Journal of Biological Inorganic Chemistry Springer Berlin Heidelberg 20/3(2015-04-01), 603-613 0949-8257 20:3<603 2015 20 775