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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.

SUBMITTER: Yu Y

PROVIDER: S-EPMC3955430 | biostudies-literature | 2014 Jan

REPOSITORIES: biostudies-literature

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Direct EPR observation of a tyrosyl radical in a functional oxidase model in myoglobin during both H2O2 and O2 reactions.

Yu Yang Y Mukherjee Arnab A Nilges Mark J MJ Hosseinzadeh Parisa P Miner Kyle D KD Lu Yi Y

Journal of the American Chemical Society 20140114 4

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 ...[more]

PMID: 24383850

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