title: Direct EPR observation of a tyrosyl radical in a functional oxidase model in myoglobin during both H2O2 and O2 reactions.
abstract: Tyrosine is a conserved redox-active amino acid that plays important roles in heme-copper oxidases (HCO). Despite the widely proposed mechanism that involves a tyrosyl radical, its direct observation under O2 reduction conditions remains elusive. Using a functional oxidase model in myoglobin called F33Y-Cu(B)Mb that contains an engineered tyrosine, we report herein direct observation of a tyrosyl radical during both reactions of H2O2 with oxidized protein and O2 with reduced protein by electron paramagnetic resonance spectroscopy, providing a firm support for the tyrosyl radical in the HCO enzymatic mechanism.
authors.affiliation: Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yu
authors.affiliation: Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.
authors.forename: Arnab
authors.initials: A
authors.lastname: Mukherjee
authors.affiliation: The Illinois EPR Research Center, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Nilges
authors.affiliation: Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.
authors.forename: Parisa
authors.initials: P
authors.lastname: Hosseinzadeh
authors.affiliation: Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.
authors.forename: Kyle D
authors.initials: KD
authors.lastname: Miner
authors.affiliation: Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.|Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.|Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.
authors.forename: Yi
authors.initials: Y
authors.lastname: Lu
mesh_terms: D018360:Crystallography, X-Ray; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals / Q000737:chemistry / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D009211:Myoglobin / Q000737:chemistry* / Q000378:metabolism; D010088:Oxidoreductases / Q000737:chemistry* / Q000378:metabolism; D010100:Oxygen / Q000737:chemistry* / Q000378:metabolism; D014443:Tyrosine / Q000737:chemistry* / Q000378:metabolism
chemical_list: D005609:Free Radicals; D009211:Myoglobin; D014443:Tyrosine; D006861:Hydrogen Peroxide; D010088:Oxidoreductases; D010100:Oxygen