Crowder titrations enable the quantification of driving forces for macromolecular phase separation

Area of Science:

• Biophysics
• Physical Chemistry
• Materials Science

Background:

• Macromolecular solubility influences phase separation.
• Saturation concentration and second virial coefficient quantify phase separation driving forces.
• These parameters depend on solution conditions and macromolecule properties.

Purpose of the Study:

• To demonstrate that crowder titrations can extract intrinsic driving forces for macromolecular phase separation.
• To quantify macromolecule-solvent incompatibility and saturation concentrations without crowders.
• To leverage crowder-mediated attractions for comparative assessments of phase separation.

Main Methods:

• Theoretical modeling
• Computer simulations
• In vitro experiments
• Crowder titrations

Main Results:

• Crowder titrations effectively isolate intrinsic driving forces for phase separation.
• This method determines saturation concentrations in the absence of crowders.
• It quantifies second virial coefficients reflecting macromolecule-solvent incompatibility.

Conclusions:

• Crowder titrations provide a robust method to assess intrinsic macromolecular phase separation.
• This approach facilitates comparative studies of different macromolecules.
• Understanding these forces is crucial for controlling macromolecular self-assembly.