6sgg
From Proteopedia
Crystal structure of monooxygenase RutA complexed with dioxygen under 1.5 MPa / 15 bars of oxygen pressure.
Structural highlights
Function[RUTA_ECOLI] Catalyzes the pyrimidine ring opening between N-3 and C-4 by an unusual flavin hydroperoxide-catalyzed mechanism to yield ureidoacrylate peracid. It cleaves pyrmidine rings directly by adding oxygen atoms, making a toxic ureidoacrylate peracid product which can be spontaneously reduced to ureidoacrylate. Requires the flavin reductase RutF to regenerate FMN in vivo. RutF can be substituted by Fre in vitro.[1] [2] Publication Abstract from PubMedOne 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 alpha-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. Aminoperoxide adducts expand the catalytic repertoire of flavin monooxygenases.,Matthews A, Saleem-Batcha R, Sanders JN, Stull F, Houk KN, Teufel R Nat Chem Biol. 2020 May;16(5):556-563. doi: 10.1038/s41589-020-0476-2. Epub 2020 , Feb 17. PMID:32066967[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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