The reactions being investigated in each of the three biopolymer-focused Themes require the development of analytical tools and techniques for the analysis of complex mixtures. Additionally, the prebiotic reactions that gave rise to the first monomers and the proto-biopolymers of life were certainly influenced by the chemical environment of the prebiotic earth (e.g., minerals, non-aqueous solvents, aerosols) and the availability of essential building block molecules. The CCE therefore established this crosscutting Theme that focuses on the development of analytical tools and the investigation of environment-enabled catalysts/processes that provide solutions to challenges of achieving the biopolymer-focused Theme goals.
Enzyme-free Replication in Alternative Solvents
Among the many theories for the origin and evolution of life, one of the most popular is the RNA world hypothesis. This theory states that RNA was once capable of storing and transferring genetic information as well as performing catalysis. However, there are a few challenges associated with these processes. RNA needs to be highly structured to perform catalysis. But this structure makes the replication of the sequence difficult. In addition, the duplex strands of the template-product complex need to be separated to serve as new templates, a process not favored in aqueous conditions. We have used an alternative solvent environment to overcome these challenges. This viscous solvent aids in trapping of the single strands, which can serve as templates and fold into their active conformation to perform catalysis.
The Unexpected Availability of Phosphate on the Early Earth
Phosphate is an essential component in biology, making up the backbone of DNA and RNA, while also being one of the most important components of cell membranes and metabolic pathways. Non-biological phosphate on modern Earth, however, is found bound in highly insoluble minerals that are similar in composition to bones and teeth. For decades astrobiologists have assumed that phosphate would have been found in similar minerals on an early prebiotic Earth, making it largely unavailable for incorporation into prebiological chemicals or subsequent inclusion into nascent biological systems. CCE researchers have been investigating how chemicals which would have been abundantly present on a prebiotic Earth, but not on a modern Earth, would have enhanced the availability of phosphate in the environment while also directly enabling synthesis of organophosphates. This work has shown that instead of being sequestered in insoluble phosphate reservoirs, phosphate was likely to be dynamically transferred throughout the environment and easily incorporated into early chemical processes.