Characterizing Mixed Single‐Chain Amphiphile‐Based Coacervates as a Robust Protocell System

Amphiphiles present in the early Earth's prebiotic soup have been shown to readily self-assemble into compartments. However, their assembly into coacervates remains underexplored. In this study, coacervates resulting from nonanoic acid (NA), nonanol (NOH) and tyramine have been characterized. These remain stable across a wide range of pH, temperature and salt conditions. They also efficiently sequester RNA and support nonenzymatic RNA primer extension, highlighting their potential role as protocells.

Prebiotic soup would have been a dilute pool of chemicals, which would have undergone reactions to form biologically relevant precursors during life's origin. Herein, compartments formed by liquid–liquid phase separation (LLPS) can concentrated these chemicals, thereby catalyzing their reactions. In this backdrop, LLPS-based systems are being studied, with a decanoic acid-based coacervate system recently described as a model protocell. This is in contrast to studies where fatty acids vesicles are predominantly explored as protocells. Further, exogenous delivery and endogenous synthesis of fatty acids suggest greater prevalence of shorter chain lengths of single-chain amphiphiles on the early Earth. In this backdrop, a mixed amphiphile-based coacervate system composed of nonanoic acid (NA), nonanol (NOH) and tyramine is characterized, which can form coacervates over a broad range of pHs, temperatures, and salt concentrations. This is noteworthy as compositionally heterogenous vesicles have also been shown to have advantages over pure fatty acid vesicles. Additionally, RNA sequestration is demonstrated in these coacervates, which gets enhanced upon addition of cationic amino acids, emphasizing the importance of cosolute interactions in the prebiotic soup. Nonenzymatic template-directed primer extension is also demonstrated in these coacervates, suggesting a potential functional role for these compartments during life's origin.

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