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.

背景：过氧化亚硝酸盐是一种硝化和氧化剂，是由一氧化氮和超氧自由基之间的相互作用形成的。H2A组蛋白是一种基本的核蛋白，是负责包装DNA的主要核心组蛋白之一。已经表明它们对氧化剂和硝化剂高度敏感。

目的：过氧亚硝酸盐硝化蛋白质中酪氨酸残基被认为是亚硝化损伤的标志。二酪氨酸键是蛋白质中两个酪氨酸之间的氧化共价交联键，已被越来越多地确定为氧化应激，衰老和神经退行性疾病的标志。

方法：通过各种生物物理技术评估过氧亚硝酸盐介导的H2A组蛋白的硝化和硝化作用。

结果：本研究提供的数据表明，在过氧亚硝酸盐修饰的H2A组蛋白中，二氢酪氨酸含量增加。二氢酪氨酸的形成显示荧光强度降低，FT-IR产生新峰，流体动力学尺寸增加以及H2A二级结构和三级结构的损失，导致部分折叠的结构。

结论：我们报道过氧化亚硝酸盐的有害作用在亚硝化和氧化胁迫下H2A可能发生构象和结构变化。