Related Experiment Video
Updated: Jun 19, 2026
09:26
Reconstitution of Nucleosomes with Differentially Isotope-labeled Sister Histones
Published on: March 26, 2017
Physicochemical studies on peroxynitrite-modified H3 histone
Kiran Dixit1, M Asad Khan, Y D Sharma
1Department of Biochemistry, Faculty of Medicine, Aligarh Muslim University (A.M.U.), Aligarh 202 002, Uttar Pradesh, India.
International Journal of Biological Macromolecules
|November 3, 2009
Summary
Histones protect DNA but change structure under nitrosative stress. Peroxynitrite exposure caused calf thymus H3 histone to partially fold, protecting DNA from damage.
Area of Science:
- Biochemistry
- Molecular Biology
- Structural Biology
Background:
- Histones are crucial for DNA packaging and protection within the cell nucleus.
- Nitrosative stress, involving agents like peroxynitrite, can alter protein structure and function.
- The structural response of histones to peroxynitrite is not fully understood.
Purpose of the Study:
- To investigate the structural modifications of calf thymus H3 histone upon exposure to peroxynitrite.
- To understand how H3 histone's structure changes under nitrosative stress conditions.
Main Methods:
- UV spectroscopy
- Fluorescence spectroscopy
- Circular dichroism (CD) spectroscopy
- Fourier-transform infrared (FTIR) spectroscopy
- Polyacrylamide gel electrophoresis (PAGE)
Main Results:
- Peroxynitrite-mediated oxidation and nitration induced a partially folded structure in H3 histone.
- Native H3 histone exhibits an intrinsically disordered structure.
- Spectroscopic analyses revealed significant structural alterations in modified H3 histone.
Conclusions:
- H3 histone is highly sensitive to peroxynitrite, a reactive nitrogen species.
- Under nitrosative stress, H3 histone can adopt altered structures.
- These structural changes may serve a protective role for DNA against peroxynitrite-induced damage.
Related Concept Videos
01:12The Nucleosome Core Particle
Nucleosomes are the DNA-histone complex, where the DNA strand is wound around the histone core. The histone core is an octamer containing two copies of H2A, H2B, H3, and H4 histone proteins.
Nucleosomes, paradoxically, perform two opposite functions simultaneously. On the one hand, their primary aim is to protect the delicate DNA strands from physical damage and help achieve a higher compaction ratio. On the other hand, they must allow polymerase enzymes to access histone-bound DNA during...
Nucleosomes, paradoxically, perform two opposite functions simultaneously. On the one hand, their primary aim is to protect the delicate DNA strands from physical damage and help achieve a higher compaction ratio. On the other hand, they must allow polymerase enzymes to access histone-bound DNA during...
02:10The Nucleosome Core Particle
Nucleosomes are the DNA-histone complex, where the DNA strand is wound around the histone core. The histone core is an octamer containing two copies of H2A, H2B, H3, and H4 histone proteins.
The paradox
Nucleosomes, paradoxically, perform two opposite functions simultaneously. On the one hand, their main responsibility is to protect the delicate DNA strands from physical damage and help achieve a higher compaction ratio. While on the other hand, they must allow polymerase enzymes to access DNA...
The paradox
Nucleosomes, paradoxically, perform two opposite functions simultaneously. On the one hand, their main responsibility is to protect the delicate DNA strands from physical damage and help achieve a higher compaction ratio. While on the other hand, they must allow polymerase enzymes to access DNA...
02:32Histone Modification
The histone proteins have a flexible N-terminal tail extending out from the nucleosome. These histone tails are often subjected to post-translational modifications such as acetylation, methylation, phosphorylation, and ubiquitination. Particular combinations of these modifications form “histone codes” that influence the chromatin folding and tissue-specific gene expression.
Acetylation
The enzyme histone acetyltransferase adds acetyl group to the histones. Another enzyme, histone deacetylase,...
Acetylation
The enzyme histone acetyltransferase adds acetyl group to the histones. Another enzyme, histone deacetylase,...
02:32Histone Modification
The histone proteins have a flexible N-terminal tail extending out from the nucleosome. These histone tails are often subjected to post-translational modifications such as acetylation, methylation, phosphorylation, and ubiquitination. Particular combinations of these modifications form “histone codes” that influence the chromatin folding and tissue-specific gene expression.
Acetylation
The enzyme histone acetyltransferase adds acetyl group to the histones. Another enzyme, histone deacetylase,...
Acetylation
The enzyme histone acetyltransferase adds acetyl group to the histones. Another enzyme, histone deacetylase,...
02:25Spreading of Chromatin Modifications
The histone proteins in the nucleosomes are post-translationally modified (PTM) to increase or decrease access to DNA. The commonly observed PTMs are methylation, acetylation, phosphorylation, and ubiquitination of lysine amino acids in the histone H3 tail region. These histone modifications have specific meaning for the cell. Hence, they are called "histone code". The protein complex involved in histone modification is termed as "reader-writer" complex.
Writers
The writer is an enzyme that can...
Writers
The writer is an enzyme that can...
02:04Covalently Linked Protein Regulators
Proteins can undergo many types of post-translational modifications, often in response to changes in their environment. These modifications play an important role in the function and stability of these proteins. Covalently linked molecules include functional groups, such as methyl, acetyl, and phosphate groups, and also small proteins, such as ubiquitin. There are around 200 different types of covalent regulators that have been identified.
These groups modify specific amino acids in a protein.
These groups modify specific amino acids in a protein.