title: Chemoselective, Enzymatic C-H Bond Amination Catalyzed by a Cytochrome P450 Containing an Ir(Me)-PIX Cofactor.
abstract: Cytochrome P450 enzymes have been engineered to catalyze abiological C-H bond amination reactions, but the yields of these reactions have been limited by low chemoselectivity for the amination of C-H bonds over competing reduction of the azide substrate to a sulfonamide. Here we report that P450s derived from a thermophilic organism and containing an iridium porphyrin cofactor (Ir(Me)-PIX) in place of the heme catalyze enantioselective intramolecular C-H bond amination reactions of sulfonyl azides. These reactions occur with chemoselectivity for insertion of the nitrene units into C-H bonds over reduction of the azides to the sulfonamides that is higher and with substrate scope that is broader than those of enzymes containing iron porphyrins. The products from C-H amination are formed in up to 98% yield and ∼300 TON. In one case, the enantiomeric excess reaches 95:5 er, and the reactions can occur with divergent site selectivity. The chemoselectivity for C-H bond amination is greater than 20:1 in all cases. Variants of the Ir(Me)-PIX CYP119 displaying these properties were identified rapidly by evaluating CYP119 mutants containing Ir(Me)-PIX in cell lysates, rather than as purified enzymes. This study sets the stage to discover suitable enzymes to catalyze challenging C-H amination reactions.
authors.affiliation: Department of Chemistry, University of California , Berkeley, California 94720, United States.|Chemical Sciences Division, Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, California 94720, United States.
authors.forename: Paweł
authors.identifier: 0000-0001-5095-4943
authors.initials: P
authors.lastname: Dydio
authors.affiliation: Department of Chemistry, University of California , Berkeley, California 94720, United States.|Chemical Sciences Division, Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, California 94720, United States.
authors.forename: Hanna M
authors.initials: HM
authors.lastname: Key
authors.affiliation: Department of Chemistry, University of California , Berkeley, California 94720, United States.|Chemical Sciences Division, Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, California 94720, United States.
authors.forename: Hiroki
authors.identifier: 0000-0003-2081-6886
authors.initials: H
authors.lastname: Hayashi
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of California , Berkeley, California 94720, United States.|Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, California 94720, United States.
authors.forename: Douglas S
authors.initials: DS
authors.lastname: Clark
authors.affiliation: Department of Chemistry, University of California , Berkeley, California 94720, United States.|Chemical Sciences Division, Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, California 94720, United States.
authors.forename: John F
authors.identifier: 0000-0002-4157-468X
authors.initials: JF
authors.lastname: Hartwig