Stapled histone H3 tails are super-substrates for lysine methyltransferase SETD7

科学分野:

• Biochemistry
• Epigenetics
• Molecular Biology

背景:

• Histone methylation, specifically H3K4 methylation catalyzed by SETD7, is crucial for epigenetic gene regulation.
• The N-terminal histone H3 tail adopts a specific conformation when binding to SETD7, positioning key residues for catalysis.

研究 の 目的:

• To design and evaluate stapled histone H3 peptides (between residues 1 and 6) as substrates and inhibitors of human SETD7.
• To explore a novel proximity-guided approach for modulating SETD7 activity.

主な方法:

• Proximity-guided design of cyclic H3 peptides with lactam linkages.
• Enzymatic assays to measure methylation activity and catalytic efficiency.
• Inhibition assays using modified stapled peptides.

主要な成果:

• Stapled H3 peptides are efficiently methylated by SETD7, significantly outperforming linear sequences.
• Cyclic H3 peptides with lactam linkages exhibit up to 110-fold higher catalytic efficiency compared to linear H3K4 peptides.
• Stapled peptides show high substrate selectivity for SETD7 over related methyltransferases (MLL3, SETD1A).
• A norleucine variant of a stapled peptide acts as a potent SETD7 inhibitor.

結論:

• Stapled histone peptides represent a novel and highly effective class of SETD7 substrates and inhibitors.
• This approach offers a promising strategy for selective modulation of SETD7 activity in epigenetic regulation.
• The findings highlight the potential of peptidomimetics in targeting epigenetic enzymes.