title: O-H Activation by an Unexpected Ferryl Intermediate during Catalysis by 2-Hydroxyethylphosphonate Dioxygenase.
abstract: Activation of O-H bonds by inorganic metal-oxo complexes has been documented, but no cognate enzymatic process is known. Our mechanistic analysis of 2-hydroxyethylphosphonate dioxygenase (HEPD), which cleaves the C1-C2 bond of its substrate to afford hydroxymethylphosphonate on the biosynthetic pathway to the commercial herbicide phosphinothricin, uncovered an example of such an O-H-bond-cleavage event. Stopped-flow UV-visible absorption and freeze-quench Mössbauer experiments identified a transient iron(IV)-oxo (ferryl) complex. Maximal accumulation of the intermediate required both the presence of deuterium in the substrate and, importantly, the use of2H2O as solvent. The ferryl complex forms and decays rapidly enough to be on the catalytic pathway. To account for these unanticipated results, a new mechanism that involves activation of an O-H bond by the ferryl complex is proposed. This mechanism accommodates all available data on the HEPD reaction.
authors.affiliation: Department of Chemistry and Howard Hughes Medical Institute, University of Illinois at Urbana-Champaign , 600 South Mathews Avenue, Urbana, Illinois 61801, United States.|Institute for Genomic Biology, University of Illinois at Urbana-Champaign , 1206 West Gregory Drive, Urbana, Illinois 61801, United States.
authors.forename: Spencer C
authors.initials: SC
authors.lastname: Peck
authors.affiliation: Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.
authors.forename: Chen
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.
authors.forename: Laura M K
authors.initials: LM
authors.lastname: Dassama
authors.affiliation: Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.
authors.forename: Bo
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.
authors.forename: Yisong
authors.identifier: 0000-0002-4132-3565
authors.initials: Y
authors.lastname: Guo
authors.affiliation: Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.
authors.forename: Lauren J
authors.initials: LJ
authors.lastname: Rajakovich
authors.affiliation: Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.|Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.
authors.forename: J Martin
authors.initials: JM
authors.lastname: Bollinger
authors.affiliation: Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.|Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.
authors.forename: Carsten
authors.identifier: 0000-0002-3302-7053
authors.initials: C
authors.lastname: Krebs
authors.affiliation: Department of Chemistry and Howard Hughes Medical Institute, University of Illinois at Urbana-Champaign , 600 South Mathews Avenue, Urbana, Illinois 61801, United States.|Institute for Genomic Biology, University of Illinois at Urbana-Champaign , 1206 West Gregory Drive, Urbana, Illinois 61801, United States.
authors.forename: Wilfred A
authors.identifier: 0000-0002-5467-7071
authors.initials: WA
authors.lastname: van der Donk
mesh_terms: D055162:Biocatalysis; D049308:Dioxygenases / Q000737:chemistry / Q000378:metabolism*; D058085:Iron Compounds / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D008968:Molecular Conformation; D063065:Organophosphonates / Q000737:chemistry / Q000378:metabolism*; D013056:Spectrophotometry, Ultraviolet; D015204:Spectroscopy, Mossbauer
chemical_list: C519566:2-hydroxyethyl phosphonate; D058085:Iron Compounds; D063065:Organophosphonates; D049308:Dioxygenases