Coacervate formation studied by explicit solvent coarse-grain molecular dynamics with the Martini model

Area of Science:

• Polymer Science
• Biophysics
• Computational Chemistry

Background:

• Complex coacervates are liquid-liquid phase separated systems formed by oppositely charged polyelectrolytes.
• They are crucial for understanding cellular compartmentalization and biomolecular condensates.
• Studying solute diffusion and partitioning within coacervates is vital due to their dynamic nature but challenging experimentally and theoretically.

Purpose of the Study:

• To develop an accurate and efficient molecular dynamics model for complex coacervates.
• To simulate the behavior of coacervates and solute partitioning at near-atomic resolution.
• To provide a versatile tool for studying coacervates and biomolecular condensates under various conditions.

Main Methods:

• Utilized an explicit-solvent, molecular dynamics coarse-grain model.
• Based the model on the Martini 3.0 force field.
• Simulated poly-lysine and poly-glutamate systems to validate salt-dependent coacervation.

Main Results:

• Successfully reproduced salt-dependent coacervation of poly-lysine and poly-glutamate systems.
• Demonstrated the model's capability to simulate ion and small nucleotide partitioning.
• Validated the model's accuracy against known coacervate behaviors.

Conclusions:

• The developed coarse-grain model accurately represents complex coacervates.
• This model enables near-atomic resolution simulations of coacervates and biomolecular condensates.
• The model facilitates the study of solute dynamics within these systems across diverse conditions.