Reaction: (1) uracil + FMNH2 + O2 + NADH = (Z)-3-ureidoacrylate + H2O + FMN + NAD+ + H+ (overall reaction)
(1a) FMNH2 + O2 = FMN-N5-peroxide
(1b) uracil + FMN-N5-peroxide = (Z)-3-ureidoacrylate + FMN-N5-oxide
(1c) FMN-N5-oxide + NADH = FMN + H2O + NAD+ + H+ (spontaneous)
(2) thymine + FMNH2 + O2 + NADH = (Z)-2-methylureidoacrylate + H2O + FMN + NAD+ + H+ (overall reaction)
(2a) FMNH2 + O2 = FMN-N5-peroxide
(2b) thymine + FMN-N5-peroxide = (Z)-2-methylureidoacrylate + FMN-N5-oxide
(2c) FMN-N5-oxide + NADH = FMN + H2O + NAD+ + H+ (spontaneous)
For diagram of reaction click here.
Glossary: (Z)-3-ureidoacrylate = (2Z)-3-(carbamoylamino)prop-2-enoate
(Z)-2-methylureidoacrylate = (2Z)-3-(carbamoylamino)-2-methylprop-2-enoate
Other name(s): rutA (gene name)
Systematic name: uracil,FMNH2:oxygen oxidoreductase (uracil hydroxylating, ring-opening)
Comments: The enzyme participates in the Rut pyrimidine catabolic pathway. The flavin-N5-oxide that is formed by the enzyme reacts spontaneously with NADH to give oxidized flavin, releasing a water molecule.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number:
References:
1. Mukherjee, T., Zhang, Y., Abdelwahed, S., Ealick, S.E. and Begley, T.P. Catalysis of a flavoenzyme-mediated amide hydrolysis. J. Am. Chem. Soc. 132 (2010) 5550-5551. [PMID: 20369853]
2. Kim, K.S., Pelton, J.G., Inwood, W.B., Andersen, U., Kustu, S. and Wemmer, D.E. The Rut pathway for pyrimidine degradation: novel chemistry and toxicity problems. J. Bacteriol. 192 (2010) 4089-4102. [PMID: 20400551]
3. Adak, S. and Begley, T.P. RutA-catalyzed oxidative cleavage of the uracil amide involves formation of a flavin-N5-oxide. Biochemistry 56 (2017) 3708-3709. [PMID: 28661684]
4. Adak, S. and Begley, T.P. Flavin-N5-oxide: A new, catalytic motif in flavoenzymology. Arch. Biochem. Biophys. 632 (2017) 4-10. [PMID: 28784589]
5. Matthews, A., Saleem-Batcha, R., Sanders, J.N., Stull, F., Houk, K.N. and Teufel, R. Aminoperoxide adducts expand the catalytic repertoire of flavin monooxygenases. Nat. Chem. Biol. 16 (2020) 556–563. [PMID: 32066967]