Molecular Mechanism underlying PRMT1 Dimerization for SAM Binding and Methylase Activity.

Area of Science:

• Biochemistry
• Molecular Biology
• Structural Biology

Background:

• Protein arginine methyltransferases (PRMTs) are crucial enzymes catalyzing arginine methylation, impacting epigenetic regulation, signal transduction, and cancer.
• Previous research indicated the importance of PRMT1's dimerization arm and N-terminal region for activity, but their structural and mechanistic roles were unclear.

Purpose of the Study:

• To investigate the structural contributions of the dimerization arm and N-terminal region to PRMT1's catalytic activity.
• To elucidate the allosteric regulation mechanism governing PRMT1 dimerization and activity.

Main Methods:

• Molecular dynamics (MD) simulations to observe conformational changes during dimerization.
• Network topological analysis to identify allosteric pathways.
• Biochemical assays to validate the role of identified residues in methylation activity.

Main Results:

• MD simulations revealed conformational changes in the dimerization arm and N-terminal region upon PRMT1 dimerization.
• A correlated network analysis identified an allosteric pathway connecting these distant regions.
• Mutations along the allosteric pathway significantly reduced PRMT1 methylation activity, likely by disrupting dimer formation and S-adenosyl-L-methionine (SAM) binding.

Conclusions:

• PRMT1 dimerization involves conformational rearrangements mediated by an allosteric pathway.
• Dimer formation is essential for efficient SAM binding and catalytic methylation.
• This study establishes a novel approach combining MD simulations, network analysis, and biochemical assays to study allosteric regulation in PRMTs.