Shape transformations in peptide-DNA coacervates driven by enzyme-catalyzed deacetylation

Area of Science:

• Biochemistry
• Cell Biology
• Biophysics

Background:

• Biomolecular condensates, formed via liquid-liquid phase separation (LLPS), organize cellular biochemistry.
• Enzymatic regulation of condensate formation is known, but their influence on condensate shape and transformation is less understood.

Purpose of the Study:

• To investigate how enzymatic reactions, specifically sirtuin-3 deacetylation of peptides with DNA, influence condensate shape and dynamics.
• To model and understand the transformation of gel-like aggregates to liquid-like droplets in condensates.

Main Methods:

• Designed a model system using sirtuin-3, peptides, and DNA to form condensates.
• Varied sirtuin-3 concentration and salt concentration to observe condensate transformations.
• Analyzed condensate morphology, including gel-like aggregates and spherical droplets, fusion, and wetting.

Main Results:

• Condensates initially formed gel-like aggregates that transitioned to spherical, liquid-like droplets.
• Increased sirtuin-3 concentration accelerated the gel-to-liquid condensate transformation.
• DNA bending by peptides influenced condensate properties, with distinct behaviors observed for double-stranded vs. single-stranded DNA and varying salt concentrations.

Conclusions:

• Enzymes can actively induce shape transformations in biomolecular condensates.
• Condensate material properties (gel-like vs. liquid-like) may not directly correlate with their stability.
• This study provides a framework for understanding enzyme-driven regulation of condensate morphology and function.