Bartesaghi 2017 Arch Biochem Biophys

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Bartesaghi S, Herrera D, Martinez DM, Petruk A, Demicheli V, Trujillo M, Martí MA, Estrín DA, Radi R (2017) Tyrosine oxidation and nitration in transmembrane peptides is connected to lipid peroxidation. Arch Biochem Biophys 622:9-25.

» PMID: 28412156

Bartesaghi S, Herrera D, Martinez DM, Petruk A, Demicheli V, Trujillo M, Marti MA, Estrin DA, Radi R (2017) Arch Biochem Biophys

Abstract: Tyrosine nitration is an oxidative post-translational modification that can occur in proteins associated to hydrophobic bio-structures such as membranes and lipoproteins. In this work, we have studied tyrosine nitration in membranes using a model system consisting of phosphatidylcholine liposomes with pre-incorporated tyrosine-containing 23 amino acid transmembrane peptides. Tyrosine residues were located at positions 4, 8 or 12 of the amino terminal, resulting in different depths in the bilayer. Tyrosine nitration was accomplished by exposure to peroxynitrite and a peroxyl radical donor or hemin in the presence of nitrite. In egg yolk phosphatidylcholine liposomes, nitration was highest for the peptide with tyrosine at position 8 and dramatically increased as a function of oxygen levels. Molecular dynamics studies support that the proximity of the tyrosine phenolic ring to the linoleic acid peroxyl radicals contributes to the efficiency of tyrosine oxidation. In turn, α-tocopherol inhibited both lipid peroxidation and tyrosine nitration. The mechanism of tyrosine nitration involves a "connecting reaction" by which lipid peroxyl radicals oxidize tyrosine to tyrosyl radical and was fully recapitulated by computer-assisted kinetic simulations. Altogether, this work underscores unique characteristics of the tyrosine oxidation and nitration process in lipid-rich milieu that is fueled via the lipid peroxidation process.

Copyright © 2017 Elsevier Inc. All rights reserved.

Keywords: Free radicals, Lipid peroxidation, Liposomes, Membranes, Peroxynitrite, Tyrosine nitration Bioblast editor: Kandolf G, Gnaiger E O2k-Network Lab: UY Montevideo Radi R


Labels:

Stress:Oxidative stress;RONS 


Preparation: Oxidase;biochemical oxidation 

Regulation: Oxygen kinetics 


HRR: Oxygraph-2k 

2017-07