Spontaneous emergence of membrane-forming protoamphiphiles from a lipid-amino acid mixture under wet-dry cycles

Dynamic interplay between peptide synthesis and membrane assembly would have been crucial for the emergence of protocells on the prebiotic Earth. However, the effect of membrane-forming amphiphiles on peptide synthesis, under prebiotically plausible conditions, remains relatively unexplored. Here we discern the effect of a phospholipid on peptide synthesis using a non-activated amino acid, under wet-dry cycles. We report two competing processes simultaneously forming peptides and N-acyl amino acids (NAAs) in a single-pot reaction from a common set of reactants. NAA synthesis occurs via an ester-amide exchange, which is the first demonstration of this phenomenon in a lipid-amino acid system. Furthermore, NAAs self-assemble into vesicles at acidic pH, signifying their ability to form protocellular membranes under acidic geothermal conditions. Our work highlights the importance of exploring the co-evolutionary interactions between membrane assembly and peptide synthesis, having implications for the emergence of hitherto uncharacterized compounds of unknown prebiotic relevance.

Automated summary

The study reveals the impact of phospholipids on peptide synthesis in a non-activated amino acid system under wet-dry cycles, demonstrating the simultaneous formation of peptides and N-acyl amino acids through ester-amide exchange. Furthermore, the ability of NAAs to self-assemble into vesicles at acidic pH suggests their potential for forming protocellular membranes under acidic geothermal conditions.