Peptides at Vesicle and Mineral Prebiotic Interfaces

The origin of life likely involved a complex interplay between organic molecules and mineral surfaces, yet the molecular details of these interactions remain poorly understood. Over recent decades, considerable research has focused on the individual roles of key biomolecules-such as RNA, lipids, and proteins-in early abiogenesis. As the emergence of life likely involved networks of molecular interactions that collectively shaped early functional assemblies, we focused our study on examination of the ability of peptides-arguably one of the most abundant early polymers-to interact with mineral surfaces and lipid vesicles, which served as proxies for prebiotic interfaces and compartments, respectively. Using peptide libraries constructed from either prebiotically plausible or contemporary amino acids, we demonstrated that while acidic residues drive peptide binding to mineral surfaces (such as to fluorapatite surfaces, studied here), the inclusion of arginine-a basic residue that may have been accessible in specific prebiotic environments-can synergistically enhance the mobilization of bioavailable phosphate from geological reservoirs. Furthermore, we observed a functional divergence in vesicle interactions: While prebiotic alphabets promoted dynamic membrane behaviors such as budding, libraries with "late" canonical amino acids helped preserve vesicle integrity against salt-induced collapse. Our findings support the hypothesis that interactions with peptides can elicit changes in both prebiotically relevant minerals and vesicles, which underscores the importance of studying these features as components of a system. Key Words: Origins of life-Peptides-Minerals-Vesicles-Prebiotic compartments-Amino acid alphabet evolution. Astrobiology xx, xxx-xxx.