title: Genetic and functional characterization of a novel meta-pathway for degradation of naringenin in Herbaspirillum seropedicae SmR1.
abstract: In this study, a random mutant library of Herbaspirillum seropedicae SmR1 was constructed by Tn5 insertion and a mutant incapable of utilizing naringenin as a carbon source was isolated. The Tn5 transposon was found to be inserted in the fdeE gene (Hsero_1007), which encodes a monooxygenase. Two other mutant strains in fdeC (Hsero_1005) and fdeG (Hsero_1009) genes coding for a dioxygenase and a putative cyclase, respectively, were obtained by site-directed mutagenesis and then characterized. Liquid Chromatography coupled to mass spectrometry (LC-MS)/MS analyses of culture supernatant from the fdeE mutant strain revealed that naringenin remained unaltered, suggesting that the FdeE protein is involved in the initial step of naringenin degradation. LC-MS/MS analyses of culture supernatants from the wild-type (SmR1) and FdeC deficient mutant suggested that in H. seropedicae SmR1 naringenin is first mono-oxygenated by the FdeE protein, to produce 5,7,8-trihydroxy-2-(4-hydroxyphenyl)-2,3-dihydro-4H-chromen-4-one, that is subsequently dioxygenated and cleaved at the A-ring by the FdeC dioxygenase, since the latter compound accumulated in the fdeC strain. After meta-cleavage of the A-ring, the subsequent metabolic steps generate oxaloacetic acid that is metabolized via the tricarboxylic acid cycle. This bacterium can also modify naringenin by attaching a glycosyl group to the B-ring or a methoxy group to the A-ring, leading to the generation of dead-end products.
authors.affiliation: Department of Biochemistry and Molecular Biology, Nitrogen Fixation Group, UFPR, Brazil.
authors.forename: Anelis
authors.initials: A
authors.lastname: Maria Marin
authors.affiliation: Department of Environmental Protection, Estación Experimental del Zaídin CSIC, Spain.
authors.forename: Jésus
authors.initials: J
authors.lastname: de la Torre
authors.affiliation: Department of Chemistry, UFPR, Brazil.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Ricardo Marques Oliveira
authors.affiliation: Department of Chemistry, UFPR, Brazil.
authors.forename: Andersson
authors.initials: A
authors.lastname: Barison
authors.affiliation: Department of Biochemistry and Molecular Biology, Nitrogen Fixation Group, UFPR, Brazil.
authors.forename: Leda
authors.initials: L
authors.lastname: Satie Chubatsu
authors.affiliation: Department of Biochemistry and Molecular Biology, Nitrogen Fixation Group, UFPR, Brazil.
authors.forename: Rose
authors.initials: R
authors.lastname: Adele Monteiro
authors.affiliation: Department of Biochemistry and Molecular Biology, Nitrogen Fixation Group, UFPR, Brazil.
authors.forename: Fabio
authors.initials: F
authors.lastname: de Oliveira Pedrosa
authors.affiliation: Department of Biochemistry and Molecular Biology, Nitrogen Fixation Group, UFPR, Brazil.
authors.forename: Emanuel
authors.initials: E
authors.lastname: Maltempi de Souza
authors.affiliation: Department of Genetics, UFPR, Brazil.
authors.forename: Roseli
authors.initials: R
authors.lastname: Wassem
authors.affiliation: Department of Environmental Protection, Estación Experimental del Zaídin CSIC, Spain.
authors.forename: Estrella
authors.initials: E
authors.lastname: Duque
authors.affiliation: Department of Environmental Protection, Estación Experimental del Zaídin CSIC, Spain.|Department of Biotechnology, Abengoa Research, Spain.
authors.forename: Juan-Luis
authors.initials: JL
authors.lastname: Ramos
mesh_terms: D001673:Biodegradation, Environmental; D044950:Flavanones / Q000378:metabolism*; D042803:Herbaspirillum / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism; D053719:Tandem Mass Spectrometry
chemical_list: D044950:Flavanones; D006899:Mixed Function Oxygenases; C005273:naringenin