The effects of protein charge patterning on complex coacervation.

Area of Science:

• Biochemistry
• Materials Science
• Biophysics

Background:

• Complex coacervation is crucial for protein encapsulation and understanding cellular coacervates.
• Predictive models for protein coacervates are lacking, hindering tunable design.
• Protein-specific parameters influencing coacervation remain largely unexplored.

Purpose of the Study:

• To investigate the impact of protein charge patterning on complex coacervation.
• To establish a foundation for predictive models of protein coacervate behavior.
• To explore how sequence-specific polypeptide tags influence protein coacervation thermodynamics.

Main Methods:

• Utilized sequence-specific, polypeptide-tagged Green Fluorescent Protein (GFP) variants.
• Studied complex coacervation with a synthetic polyelectrolyte.
• Analyzed phase behavior and binodal phase boundaries.

Main Results:

• Protein charge patterning was found to dictate the binodal phase boundary of coacervates.
• Achieved protein concentrations exceeding 100 mg mL-1 in the coacervate phase.
• Demonstrated that polypeptide charge patterning offers entropic advantages over isotropic patterns.

Conclusions:

• Modest alterations in polypeptide tag sequences significantly impact coacervation thermodynamics.
• Charge patterning provides a mechanism to tune the phase behavior of proteins and polypeptides.
• Findings pave the way for designing coacervates with predictable structure-function relationships.