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Updated: Aug 6, 2025
14:32
Deacetylation Assays to Unravel the Interplay between Sirtuins SIRT2 and Specific Protein-substrates
Published on: February 27, 2016
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Structural Basis of Sirtuin 6-Catalyzed Nucleosome Deacetylation
Zhipeng A Wang1,2, Jonathan W Markert3, Samuel D Whedon1,2
1Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts 02115, United States.
Journal of the American Chemical Society
|March 17, 2023
Summary
Sirtuin 6 (Sirt6) efficiently deacetylates histone H3 on nucleosomes, not free histones. Structural analysis reveals Sirt6 interacts with nucleosomal DNA and H2A/H2B, explaining its targeted chromatin regulation.
Area of Science:
- Biochemistry
- Molecular Biology
- Epigenetics
Background:
- Histone acetylation regulates gene expression and chromatin structure.
- Sirtuins are NAD-dependent deacetylases influencing DNA repair, transcription, and aging.
- Sirtuin 6 (Sirt6) is a key enzyme in this family.
Purpose of the Study:
- To investigate the substrate specificity of Sirt6.
- To elucidate the structural basis for Sirt6's activity on nucleosomes.
- To understand how Sirt6 targets specific histone acetylation sites.
Main Methods:
- Chemical modification of histone H3 at Lys9.
- Cryo-electron microscopy (cryo-EM) structural analysis.
- Biochemical assays for deacetylation activity.
Main Results:
- Sirt6 efficiently deacetylates histone H3 acetylation sites within nucleosomes, but not free histone H3.
- Cryo-EM structure reveals Sirt6 interactions with nucleosomal DNA and the H2A/H2B acidic patch.
- These interactions explain Sirt6's preference for nucleosomal H3 sites and avoidance of H2B acetylation.
Conclusions:
- Sirt6 exhibits nucleosome-specific deacetylation activity.
- The structure provides a mechanistic understanding of Sirt6's targeting and regulation of chromatin.
- Findings offer a new framework for understanding histone deacetylase (HDAC) function in chromatin regulation.
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