Multivalent polymers can control phase boundary, dynamics, and organization of liquid-liquid phase separation

Area of Science:

• Biophysics
• Molecular Biology
• Computational Biology

Background:

• Multivalent polymers like RNA and proteins are essential for biocondensate formation.
• Changes in biocondensate dynamics are linked to neurodegenerative diseases (e.g., ALS, Alzheimer's).
• Understanding polymer structure-biocondensate relationships is vital for disease treatment.

Purpose of the Study:

• Investigate differences between non-specific and specific multivalent binding polymers.
• Analyze how polymer structure influences biocondensate formation and dynamics.
• Explore the role of binding energy, solvent conditions, and polymer length in phase separation.

Main Methods:

• Coarse-grain Brownian Dynamics simulations.
• Reactive binding mimicking specific interactions.
• Modeling of three-component systems (polymer, protein, solvent).

Main Results:

• Non-specific binding polymers induce larger droplet formation changes at lower interaction energies compared to specific ones.
• Solvent conditions and polymer length significantly affect phase separation.
• Modulating binding energy alters droplet organization within the system.
• Lower protein solubility and higher protein-polymer affinity slow down condensed phase dynamics.

Conclusions:

• Non-specific interactions play a significant role in biocondensate formation.
• Multivalent polymers can be modulated to control liquid-liquid phase separation (LLPS).
• Findings provide insights into biocondensate behavior relevant to neurodegenerative diseases.