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Updated: May 8, 2026
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Site Specific Lysine Acetylation of Histones for Nucleosome Reconstitution using Genetic Code Expansion in Escherichia coli
Published on: December 26, 2020
Enzyme-dependent lysine deprotonation in EZH2 catalysis
D Randal Kipp1, Christopher M Quinn, Pascal D Fortin
1Novartis Institutes for Biomedical Research , 250 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.
Biochemistry
|September 5, 2013
Summary
Protein lysine methyltransferases, like EZH2, are crucial in epigenetics and cancer. This study reveals EZH2
Area of Science:
- Biochemistry
- Epigenetics
- Enzymology
Background:
- Protein lysine methyltransferases (PKMTs), including EZH2, are vital epigenetic regulators implicated in various diseases, notably cancers.
- EZH2 catalyzes the methylation of histone H3 at lysine 27 (H3K27), a process critical for gene silencing.
- A specific mutation, Y641F, alters EZH2's catalytic activity, promoting H3K27 trimethylation and contributing to tumor development.
Purpose of the Study:
- To elucidate the chemical mechanism of methyl transfer by wild-type (WT) EZH2 and its oncogenic Y641F mutant.
- To investigate the role of lysine deprotonation in the catalytic cycle of EZH2.
- To compare the catalytic mechanisms of WT EZH2 and the Y641F mutant.
Main Methods:
- Utilized pH-rate profiles and solvent kinetic isotope effects (sKIEs) to probe the reaction mechanism.
- Employed a histone H3-derived peptide substrate [H3(21-44)] for enzymatic assays.
- Integrated experimental findings with existing computational models.
Main Results:
- Data strongly support an enzyme-dependent deprotonation of lysine as a key, rate-limiting step in EZH2 catalysis.
- The mechanism of lysine deprotonation and the rate-limiting steps remain consistent between WT EZH2 and the Y641F mutant.
- Experimental results align with computational models suggesting enzyme-mediated solvent access for deprotonation.
Conclusions:
- Lysine deprotonation is an enzyme-controlled, rate-limiting step in EZH2-mediated methylation.
- The catalytic mechanism governing the rate is conserved between WT and Y641F EZH2.
- Substrate specificity determinants in EZH2 are distinct from the factors controlling the steady-state catalytic rate.
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