Publications

• Flavin-N5-oxide: A new, catalytic motif in flavoenzymology.

  Adak S., Begley T.P.

  Flavin-N5-oxide is a recently discovered intermediate used by EncM (1,3-diketone oxidation), DszA (sulfone monooxygenase) and RutA (amide monooxygenase). This review describes the mechanism of these enzymes and proposes criteria for the identification of additional Flavin-N5-oxide dependent enzyme ... >> More

  Flavin-N5-oxide is a recently discovered intermediate used by EncM (1,3-diketone oxidation), DszA (sulfone monooxygenase) and RutA (amide monooxygenase). This review describes the mechanism of these enzymes and proposes criteria for the identification of additional Flavin-N5-oxide dependent enzymes. << Less

  Arch Biochem Biophys 632:4-10(2017) [PubMed] [EuropePMC]

  This publication is cited by 6 other entries.

• The Rut pathway for pyrimidine degradation: novel chemistry and toxicity problems.

  Kim K.S., Pelton J.G., Inwood W.B., Andersen U., Kustu S., Wemmer D.E.

  The Rut pathway is composed of seven proteins, all of which are required by Escherichia coli K-12 to grow on uracil as the sole nitrogen source. The RutA and RutB proteins are central: no spontaneous suppressors arise in strains lacking them. RutA works in conjunction with a flavin reductase (RutF ... >> More

  The Rut pathway is composed of seven proteins, all of which are required by Escherichia coli K-12 to grow on uracil as the sole nitrogen source. The RutA and RutB proteins are central: no spontaneous suppressors arise in strains lacking them. RutA works in conjunction with a flavin reductase (RutF or a substitute) to catalyze a novel reaction. It directly cleaves the uracil ring between N-3 and C-4 to yield ureidoacrylate, as established by both nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry. Although ureidoacrylate appears to arise by hydrolysis, the requirements for the reaction and the incorporation of (18)O at C-4 from molecular oxygen indicate otherwise. Mass spectrometry revealed the presence of a small amount of product with the mass of ureidoacrylate peracid in reaction mixtures, and we infer that this is the direct product of RutA. In vitro RutB cleaves ureidoacrylate hydrolytically to release 2 mol of ammonium, malonic semialdehyde, and carbon dioxide. Presumably the direct products are aminoacrylate and carbamate, both of which hydrolyze spontaneously. Together with bioinformatic predictions and published crystal structures, genetic and physiological studies allow us to predict functions for RutC, -D, and -E. In vivo we postulate that RutB hydrolyzes the peracid of ureidoacrylate to yield the peracid of aminoacrylate. We speculate that RutC reduces aminoacrylate peracid to aminoacrylate and RutD increases the rate of spontaneous hydrolysis of aminoacrylate. The function of RutE appears to be the same as that of YdfG, which reduces malonic semialdehyde to 3-hydroxypropionic acid. RutG appears to be a uracil transporter. << Less

  J. Bacteriol. 192:4089-4102(2010) [PubMed] [EuropePMC]

  This publication is cited by 11 other entries.

• Aminoperoxide adducts expand the catalytic repertoire of flavin monooxygenases.

  Matthews A., Saleem-Batcha R., Sanders J.N., Stull F., Houk K.N., Teufel R.

  One of the hallmark reactions catalyzed by flavin-dependent enzymes is the incorporation of an oxygen atom derived from dioxygen into organic substrates. For many decades, these flavin monooxygenases were assumed to use exclusively the flavin-C4a-(hydro)peroxide as their oxygen-transferring interm ... >> More

  One of the hallmark reactions catalyzed by flavin-dependent enzymes is the incorporation of an oxygen atom derived from dioxygen into organic substrates. For many decades, these flavin monooxygenases were assumed to use exclusively the flavin-C4a-(hydro)peroxide as their oxygen-transferring intermediate. We demonstrate that flavoenzymes may instead employ a flavin-N5-peroxide as a soft α-nucleophile for catalysis, which enables chemistry not accessible to canonical monooxygenases. This includes, for example, the redox-neutral cleavage of carbon-hetero bonds or the dehalogenation of inert environmental pollutants via atypical oxygenations. We furthermore identify a shared structural motif for dioxygen activation and N5-functionalization, suggesting a conserved pathway that may be operative in numerous characterized and uncharacterized flavoenzymes from diverse organisms. Our findings show that overlooked flavin-N5-oxygen adducts are more widespread and may facilitate versatile chemistry, thus upending the notion that flavin monooxygenases exclusively function as nature's equivalents to organic peroxides in synthetic chemistry. << Less

  Nat Chem Biol 16:556-563(2020) [PubMed] [EuropePMC]

  This publication is cited by 3 other entries.

• RutA-Catalyzed Oxidative Cleavage of the Uracil Amide Involves Formation of a Flavin-N5-oxide.

  Adak S., Begley T.P.

  RutA is a novel flavoenzyme on the uracil catabolic pathway that catalyzes uracil ring opening by a unique amide oxidation reaction. Here we provide evidence that this reaction also involves the formation of a flavin-N5-oxide.

  Biochemistry 56:3708-3709(2017) [PubMed] [EuropePMC]

  This publication is cited by 3 other entries.

• Catalysis of a flavoenzyme-mediated amide hydrolysis.

  Mukherjee T., Zhang Y., Abdelwahed S., Ealick S.E., Begley T.P.

  A new pyrimidine catabolic pathway (the Rut pathway) was recently discovered in Escherichia coli K12. In this pathway, uracil is converted to 3-hydroxypropionate, ammonia, and carbon dioxide. The seven-gene Rut operon is required for this conversion. Here we demonstrate that the flavoenzyme RutA c ... >> More

  A new pyrimidine catabolic pathway (the Rut pathway) was recently discovered in Escherichia coli K12. In this pathway, uracil is converted to 3-hydroxypropionate, ammonia, and carbon dioxide. The seven-gene Rut operon is required for this conversion. Here we demonstrate that the flavoenzyme RutA catalyzes the initial uracil ring-opening reaction to give 3-ureidoacrylate. This reaction, while formally a hydrolysis reaction, proceeds by an oxidative mechanism initiated by the addition of a flavin hydroperoxide to the C4 carbonyl. While peroxide-catalyzed amide hydrolysis has chemical precedent, we are not aware of a prior example of analogous chemistry catalyzed by flavin hydroperoxides. This study further illustrates the extraordinary catalytic versatility of the flavin cofactor. << Less

  J. Am. Chem. Soc. 132:5550-5551(2010) [PubMed] [EuropePMC]

  This publication is cited by 4 other entries.