Protein-RNA complexation driven by the charge regulation mechanism

Area of Science:

• Biophysics
• Computational Biology
• Molecular Biology

Background:

• Electrostatic interactions are fundamental to biomolecular association and function.
• Mesoscopic forces, including ion-ion correlation and proton fluctuations, significantly influence molecular organization.
• Charge regulation, arising from titrating residues, is a key electrostatic mechanism driving molecular interactions.

Purpose of the Study:

• To investigate the role of charge regulation in protein-RNA interactions.
• To develop a computational model for studying protein-RNA complexation.
• To analyze the complexation of the p19 viral protein with small interfering RNA under varying conditions.

Main Methods:

• Development of a novel molecular model using constant-pH Monte Carlo simulations.
• Implementation of a fast coarse-grained titration proton scheme.
• Investigation of protein-RNA interactions at different pH and salt concentrations.

Main Results:

• Charge regulation significantly enhances the association between protein and RNA molecules.
• The effect of charge regulation is more pronounced in protein-RNA systems due to RNA's high negative charge.
• Simulation outcomes align with predictions from the Kirkwood-Shumaker theory.

Conclusions:

• Charge regulation is a critical factor in macromolecular complexation, particularly for RNA-protein interactions.
• The developed computational model provides insights into the electrostatic mechanisms governing these interactions.
• Understanding these electrostatic forces is essential for comprehending the extensive role of RNA in cellular processes.