Regulation of Chemical Transformation in Designer Peptide Biomolecular Condensates

Biomolecular condensates, formed through liquid-liquid phase separation (LLPS), serve as dynamic platforms for biochemical regulation. Inspired by these natural systems, we developed designer peptide-based condensates to modulate chemical transformations, focusing on the Cu(I)-catalyzed azide-alkyne cycloaddition click reaction between hydrophobic reactants as a model system. By incorporating varying number of isoleucine residues into peptide sequences, we tuned hydrophobicity of the condensates, influencing reaction rate and conversion. Condensates formed by a peptide with a single isoleucine enhanced reactant recruitment and reaction efficiency, while excessive hydrophobicity resulted in solid-like condensates that impeded catalysis. Notably, we deciphered the factors that affect reactant recruitment, eventually resulting in a complete spatial regulation of product localization inside the condensates. The study highlights the critical balance of hydrophobicity for optimal reaction performance in condensates, demonstrating a new approach to regulate chemical transformations in water-based systems. This work establishes a foundation for engineering biomolecular condensates as green chemistry platforms and reaction vessels for applications in biotechnology and biomedicine.