In a recent review paper, a team of scientists examine how ribonucleic acid (RNA) may have functioned shortly after life’s origin on Earth during the Archean Eon (2.5 to 4 billion years ago). Many scientists believe that RNA was the single biopolymer for the earliest cells on our planet, or was at least one among a small group of biopolymers.

During the Archean, Earth’s atmosphere was anoxic and there was abundant Fe2+. The research team hypothesizes that RNA could have used Fe2+ as a dominant cofactor instead of Mg2+ (which is commonly contained in RNA polymerase today). This could have been the case for RNA activity until oxygen began to make up a significant portion of the atmosphere following the Great Oxidation Event. The review discusses experimental work on the interactions of Fe2+ and proteins that process RNA and nucleic acids under anoxic conditions.

The scientists predict that Fe2+ could have participated in numerous RNA functions, including folding and catalysis. If true, this relationship between Fe2+ and nucleic acid structure and function could provide a link between ancient biology and the geological record.

The study, “Folding and Catalysis Near Life’s Origin: Support for Fe2+ as a Dominant Divalent Cation,” was published in the journal Prebiotic Chemistry and Chemical Evolution of Nucleic Acids. The work was performed at the NSF/NASA Center for Chemical Evolution (CCE) at the Georgia Institute of Technology in Atlanta, Georgia. The CCE is a collaborative program supported by the National Science Foundation (NSF) and the NASA Astrobiology Program.