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Peroxynitrite-Mediated Structural Changes in Histone H2A: Biochemical and Biophysical Analysis

[ Vol. 27 , Issue. 10 ]

Author(s):

Md. Asad Khan*, Md. Faiz Akram, Khursheed Alam, Haseeb Ahsan and Moshahid A. Rizvi   Pages 989 - 998 ( 10 )

Abstract:


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 diseases.

Methods: Peroxinitrite-mediated nitration and dinitration in H2A histone was assessed by various biophysical techniques.

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.

Keywords:

H2A histone, peroxynitrite, dityrosine, fluorescence, protein nitration, nitration.

Affiliation:

Faculty of Dentistry, Jamia Millia Islamia, New Delhi-110025, Faculty of Dentistry, Jamia Millia Islamia, New Delhi-110025, Department of Biochemistry, Faculty of Medicine, Aligarh Muslim University, Aligarh-202002, Faculty of Dentistry, Jamia Millia Islamia, New Delhi-110025, Department of Biosciences, Jamia Millia Islamia, New Delhi-110025



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