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Ni II ‐ATCUN‐Catalyzed Tyrosine Nitration in the Presence of Nitrite and Sulfite
Author(s) -
Maiti Biplab K.,
Maia Luisa B.,
Moura Isabel,
Moura José J. G.
Publication year - 2019
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201806228
Subject(s) - sulfite , chemistry , tyrosine , nitration , reactive nitrogen species , sulfur metabolism , biochemistry , nitrite , nitric oxide , in vivo , nitrosylation , stereochemistry , metabolism , reactive oxygen species , organic chemistry , nitrate , biology , microbiology and biotechnology
The nitration of tyrosine residues in proteins represents a specific footprint of the formation of reactive nitrogen species (RNS) in vivo. Here, the fusion product of orange protein (ATCUN‐ORP) was used as an in vitro model system containing an amino terminal Cu(II)‐ and Ni(II)‐binding motif (ATCUN) tag at the N‐terminus and a native tyrosine residue in the metal‐cofactor‐binding region for the formation of 3‐NO 2 ‐Tyr (3‐NT). It is shown that Ni II ‐ATCUN unusually performs nitration of tyrosine at physiological pH in the presence of the NO 2 − /SO 3 2− /O 2 system, which is revealed by a characteristic absorbance band at 430 nm in basic medium and 350 nm in acidic medium (fingerprint of 3‐NT). Kinetics studies showed that the formation of 3‐NT depends on sulfite concentration over nitrite concentration suggesting key intermediate products, identified as oxysulfur radicals, which are detected by spin‐trap EPR study by using 5,5‐dimethyl‐1‐pyrroline‐N‐oxide (DMPO). This study describes a new route in the formation of 3‐NT, which is proposed to be linked with the sulfur metabolism pathway associated with the progression of disease occurrence in vivo.