Methyltransferase Inhibitors: Competing with, or Exploiting the Bound Cofactor

Area of Science:

• Biochemistry
• Chemical Biology
• Epigenetics

Background:

• Protein methyltransferases (PMTs) are crucial enzymes regulating cellular functions through epigenetic mechanisms and DNA repair.
• PMTs are significant targets in chemical biology and drug discovery due to their roles in cellular identity and function.
• The enzymatic activity of PMTs relies on the transfer of a methyl group from S-adenosylmethionine (SAM) to a substrate protein.

Purpose of the Study:

• To review strategies employed by chemical inhibitors to target protein methyltransferases.
• To explore how the essential cofactor S-adenosylmethionine (SAM) is leveraged by these inhibitors.
• To discuss structural insights into inhibitor design and their interaction with PMTs and SAM.

Main Methods:

• Review of structural studies and clinical data on PMT inhibitors.
• Analysis of cofactor binding pocket interactions and alternative binding modes.
• Examination of substrate competition and allosteric inhibition mechanisms.

Main Results:

• Inhibitors can compete with SAM by occupying adjacent pockets or inducing conformational changes for a more druggable site.
• Some inhibitors target the substrate binding site, utilizing bound SAM for allosteric stabilization or direct interaction.
• Structural insights reveal diverse strategies for PMT inhibition, overcoming challenges posed by the cofactor binding site's nature.

Conclusions:

• Chemical inhibitors effectively target protein methyltransferases by exploiting the essential cofactor SAM through various binding and interaction strategies.
• Understanding these mechanisms provides a foundation for developing novel therapeutics against PMT-related diseases.
• Structural biology plays a critical role in elucidating inhibitor-enzyme interactions and guiding drug design for PMTs.