Background: Peroxynitrite, a nitrating and oxidizing agent, is formed by the interaction
between nitric oxide and superoxide radicals. H2A histone is a basic nucleoprotein and is one of
the major core histones responsible for packaging DNA. It has been shown that they are highly sensitive
to oxidizing and nitrating agents.
Objective: Nitration of tyrosine residues in proteins by peroxynitrite is regarded as a marker of
nitrosative damage. The dityrosine bond, an oxidative covalent cross-link between two tyrosines in
protein, is increasingly identified as a marker of oxidative stress, aging and neurodegerative
Methods: Peroxinitrite-mediated nitration and dinitration in H2A histone was assessed by various
Results: The data presented in this study showed that the dityrosine content was found to be elevated
in H2A histone modified with peroxynitrite. The formation of dityrosine showed a decrease in
fluorescence intensity, generation of a new peak in FT-IR, increase in hydrodynamic size, and loss
of secondary and tertiary structure of H2A resulting in a partially folded structure.
Conclusion: We report that H2A may undergo conformational and structural changes under nitrosative
and oxidative stress from the deleterious effects of peroxynitrite.