title: Biocatalytic conversion of avermectin to 4"-oxo-avermectin: characterization of biocatalytically active bacterial strains and of cytochrome p450 monooxygenase enzymes and their genes.
abstract: 4"-Oxo-avermectin is a key intermediate in the manufacture of the agriculturally important insecticide emamectin benzoate from the natural product avermectin. Seventeen biocatalytically active Streptomyces strains with the ability to oxidize avermectin to 4"-oxo-avermectin in a regioselective manner have been discovered in a screen of 3,334 microorganisms. The enzymes responsible for this oxidation reaction in these biocatalytically active strains were found to be cytochrome P450 monooxygenases (CYPs) and were termed Ema1 to Ema17. The genes for Ema1 to Ema17 have been cloned, sequenced, and compared to reveal a new subfamily of CYPs. Ema1 to Ema16 have been overexpressed in Escherichia coli and purified as His-tagged recombinant proteins, and their basic enzyme kinetic parameters have been determined.
authors.affiliation: Syngenta Crop Protection AG, Basel, Switzerland.
authors.forename: Volker
authors.initials: V
authors.lastname: Jungmann
authors.forename: István
authors.initials: I
authors.lastname: Molnár
authors.forename: Philip E
authors.initials: PE
authors.lastname: Hammer
authors.forename: D Steven
authors.initials: DS
authors.lastname: Hill
authors.forename: Ross
authors.initials: R
authors.lastname: Zirkle
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Buckel
authors.forename: Dagmar
authors.initials: D
authors.lastname: Buckel
authors.forename: James M
authors.initials: JM
authors.lastname: Ligon
authors.forename: J Paul
authors.initials: JP
authors.lastname: Pachlatko
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D007559:Ivermectin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D007700:Kinetics; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013237:Stereoisomerism; D013302:Streptomyces / Q000145:classification* / Q000201:enzymology* / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D011994:Recombinant Proteins; D007559:Ivermectin; C019264:avermectin; D003577:Cytochrome P-450 Enzyme System; C108024:emamectin benzoate