The Potential Roles of Minerals in the Emergence of Protocells

The appearance of life around four billion years ago was a result of a series of geochemical events involving the interaction of a primitive atmosphere, water and minerals with simple molecules leading to the formation of biopolymers, such as lipids, nucleic acids and peptides, which are the building blocks of life. The focus of our research is to discover the potential role of minerals in the synthesis and self-assembly of these essential biomolecular components into the earliest life-like entities, proto-cells. While the involvement of minerals in prebiotic chemistry has been proposed for decades, few experimental studies exist with any mechanistic understanding of the underlying mineral structure and reactivity. My goal, as a geochemist, is to use our knowledge of mineral structure and reactivity to identify mechanistic structure-activity relationships in order to predict whether a protocell may emerge on a rocky planet or moon. In particular, we have examined the role of minerals in (i) the formation of model protocell lipid membranes, (ii) promoting the polymerization of ribonucleic acid (RNA) monomers, and (iii) acting as "prebiotic enzymes" by catalyzing transmembrane redox reactions in the development of a model protometabolism. Thus, we have identified a role for minerals in the emergence of all three essential components of a protocell, namely, the lipid membrane, information-carrying RNA and metabolism.