Evidence for the Prerequisite Formation of Phenoxyl Radicals in Radical-Mediated Peptide Tyrosine Nitration In Vacuo.
Chemistry
; 26(1): 331-335, 2020 Jan 02.
Article
em En
| MEDLINE
| ID: mdl-31657861
ABSTRACT
The elementary mechanism of radical-mediated peptide tyrosine nitration, which is a hallmark of post-translational modification of proteins under nitrative stress in vivo, has been elucidated in detail by using an integrated approach that combines the gas-phase synthesis of prototypical molecular tyrosine-containing peptide radical cations, ion-molecule reactions, and isotopic labeling experiments with DFT calculations. This reaction first involves the radical recombination of . NO2 towards the prerequisite phenoxyl radical tautomer of a tyrosine residue, followed by proton rearrangements, finally yielding the stable and regioselective 3-nitrotyrosyl residue product. In contrast, nitration with the π-phenolic radical cation tautomer is inefficient. This first direct experimental evidence for the elementary steps of the radical-mediated tyrosine nitration mechanism in the gas phase provides a fundamental insight into the regioselectivity of biological tyrosine ortho-nitration.
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01-internacional
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MEDLINE
Idioma:
En
Ano de publicação:
2020
Tipo de documento:
Article