title: Enzyme-controlled nitrogen-atom transfer enables regiodivergent C-H amination.
abstract: We recently demonstrated that variants of cytochrome P450BM3 (CYP102A1) catalyze the insertion of nitrogen species into benzylic C-H bonds to form new C-N bonds. An outstanding challenge in the field of C-H amination is catalyst-controlled regioselectivity. Here, we report two engineered variants of P450BM3 that provide divergent regioselectivity for C-H amination-one favoring amination of benzylic C-H bonds and the other favoring homo-benzylic C-H bonds. The two variants provide nearly identical kinetic isotope effect values (2.8-3.0), suggesting that C-H abstraction is rate-limiting. The 2.66-Å crystal structure of the most active enzyme suggests that the engineered active site can preorganize the substrate for reactivity. We hypothesize that the enzyme controls regioselectivity through localization of a single C-H bond close to the iron nitrenoid.
authors.affiliation: Division of Chemistry and Chemical Engineering 210-41, California Institute of Technology , 1200 East California Boulevard, Pasadena, California 91125, United States.
authors.forename: Todd K
authors.initials: TK
authors.lastname: Hyster
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Farwell
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Buller
authors.forename: John A
authors.initials: JA
authors.lastname: McIntosh
authors.forename: Frances H
authors.initials: FH
authors.lastname: Arnold
mesh_terms: D000586:Amination; D004798:Enzymes / Q000737:chemistry*; D007700:Kinetics; D009584:Nitrogen / Q000737:chemistry*
chemical_list: D004798:Enzymes; D009584:Nitrogen