Peptide-Metal Cation Coacervate Microdroplets as Membrane-free Protocells with Enhanced Light-Induced Catalysis

Area of Science:

• Origin of Life Research
• Prebiotic Chemistry
• Biomolecular Condensates

Background:

• Membrane-free coacervates are artificial life-like systems used in protocell research.
• Inorganic metal ions may have been crucial for prebiotic compartmentalization on early Earth.

Purpose of the Study:

• To investigate novel coacervate protocells formed by peptide-metal ion interactions.
• To explore the role of zinc ions in driving liquid-liquid phase separation (LLPS) for protocell formation.

Main Methods:

• Formation of coacervates via LLPS of anionic polypeptides induced by zinc ions.
• Characterization of coacervate properties, including liquid-like behavior, client partitioning, and catalysis.
• Integration of experimental data with theoretical simulations to identify phase separation pathways.

Main Results:

• Peptide-zinc ion coacervates exhibit liquid-like properties and enhanced catalysis.
• Two kinetic pathways to phase separation were identified, dependent on zinc ion concentration and coordination.
• Non-equilibrium condensates formed, influencing light-induced catalytic efficiency.

Conclusions:

• Peptide-metal ion interactions offer a plausible mechanism for prebiotic compartmentalization.
• These coacervates acted as microreactors, potentially facilitating early biochemical reactions.
• This work presents a diverse pathway for the emergence of protocells on early Earth.