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.
Do fundamental transformations in biology reflect much simpler geochemical reactions that occurred on the early Earth? With increasing sophistication, these elementary pathways may have evolved into the complex metabolism seen in modern life. Remnants of a plausible ancient proto-metabolism might be identifiable as reaction pathways and cycles that share significant molecular and mechanistic components with life, but proceed without the need for catalysts. Recently, we described two reaction cycles that mimic the citric acid (TCA) cycle, but require no enzymes or cofactors, and progress in water at mild pH and temperatures. Like the TCA, these abiotic reactions also produce amino acids, the building blocks of catalytic enzymes.
It is possible that water-free solvents may have provided excellent environments for the formation of biopolymers on the early Earth. DNA folding in a biocompatible, deep eutectic solution composed of glycerol and choline chloride was explored. In comparing folding of the DNA sequence, we observe distinct differences between the aqueous buffer and the viscous eutectic solution, suggesting that solvent properties may strongly influence the assembly and structure of biopolymers.
Researchers within the CCE explore sources of reactive phosphate that would have been a viable route to the formation of nucleotides; the low reactivity of phosphates would have been potentially limiting on the early Earth. Schreibersite, a meteoritic phosphide mineral, may have provided a reasonably plentiful source of reactive phosphorus. Studies demonstrate the phosphorylation of adenosine and uridine using synthetic schreibersite in notable yields. This study outlines a plausible mechanistic route to the phosphorylation of several biologically relevant molecules and may be integral in understanding early biological systems on Earth as well as in extraterrestrial environments.
The ability to identify and differentiate species of proto-biopolymers produced in the Center is essential to our research initiatives. We focus a concerted effort towards the development of an increasingly advanced suite of tools to facilitate these essential investigations. Most recently, CCE researchers have coupled mass spectrometry imaging (MSI) with thin layer chromatography (TLC) through a novel automated approach called Detect TLC. In short, this program automatically identifies m/z values exhibiting TLC spot-like regions and can spatially match m/z values for spots acquired during alternating high and low collision-energy scans, allowing us to enhance structural identification by pairing product ions with precursors. This software is now available for use and adaptation by users worldwide.