Mineral-Mediated Oligoribonucleotide Condensation: Broadening the Scope of Prebiotic Possibilities on the Early Earth

Simple Summary: Although life on earth is quite diverse, some biological molecules are common across all life forms, both extant and extinct, and thus are thought to have been present as life emerged. Identifying how such compounds could have formed prior to life is therefore a critical step in understanding the origin of life and the potential for life elsewhere in the solar system and beyond. One class of biomolecule crucial to modern life are nucleic acids, which carry the genetic code and are integral to cellular replication and function. In modern biology, cellular machinery synthesizes these molecules; however, prior to life's beginning, it is possible that naturally occurring minerals played a role in the synthesis and polymerization of these molecules. Only a few minerals have been tested thus far; here, we investigate a variety of minerals for their ability to promote elongation of ribonucleic acid in water. In doing so, both the minerals and their environments of formation are tested for their potential to promote elongation. We show that several newly tested minerals can promote synthesis, suggesting that a broader set of environments may have been able to host chemical reactions relevant to the origin of life than previously assumed. The origin of life on earth requires the synthesis of protobiopolymers in realistic geologic environments along strictly abiotic pathways that rely on inorganic phases (such as minerals) instead of cellular machinery to promote condensation. One such class of polymer central to biochemistry is the polynucleotides, and oligomerization of activated ribonucleotides has been widely studied. Nonetheless, the range of laboratory conditions tested to date is limited and the impact of realistic early Earth conditions on condensation reactions remains unexplored. Here, we investigate the potential for a variety of minerals to enhance oligomerization using ribonucleotide monomers as one example to model condensation under plausible planetary conditions. The results show that several minerals differing in both structure and composition enhance oligomerization. Sulfide minerals yielded oligomers of comparable lengths to those formed in the presence of clays, with galena being the most effective, yielding oligonucleotides up to six bases long. Montmorillonite continues to excel beyond other clays. Chemical pretreatment of the clay was not required, though maximum oligomer lengths decreased from similar to 11 to 6 bases. These results demonstrate the diversity of mineral phases that can impact condensation reactions and highlight the need for greater consideration of environmental context when assessing prebiotic synthesis and the origin of life.

Automated summary

This article investigates the influence of different minerals on the oligomerization of ribonucleotides under simulated planetary conditions. It finds that several minerals can enhance the synthesis and elongation of nucleic acids, suggesting a broader range of potential environments that could foster the origin of life.