Molecular Evolution of Phosphate

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The question of the prebiotic source of pyrophosphate will be pursued along two lines. One is the possibility of continuous formation in nature by condensation under high temperature acidic hydrothermal conditions and subsequent concentration in reactive minerals. The other involves the action of condensation agents, such as cyanide derivatives in an environment where such agents may be concentrated together with orthophosphate ion. Since the source components of RNA; cyanide, phosphate and carbonate (as a precursor of aldehydes) are all anionic, minerals with anion exchange capacity are our prime choice for study as potential concentrators and hosts for these components, and as catalysts for their further reaction. Possible and likely paths for prebiotic phosphorylation of sugar precursor molecules require condensed phosphates as driving agents, and, as substrates, the simplest possible achiral ester forming hydroxyl compounds, such as condensation products of formaldehyde, the latter known to form by photochemical and plasma processes. Also in this branch of the investigation, the selective concentrating power and the catalytic aid of anion sorbing transition metal hydroxide minerals will be explore. The third part of the study connects to current research on non-enzymatic oligomerization of RNA by exploring the concentration, ordering, and catalytic reaction of evolved nucleotides such as AMP and nucleotide phosphates (ADP, ATP) in the anion exchanging pyroaurite minerals. This project is a part of a larger program, that aims at demonstrating environmentally plausible processes leading from simple organic and inorganic molecules in highly dilute aqueous solution via selective concentration, ordering and reaction on mineral substrates, to the formation of molecular complexes of prebiotic interest. The present proposal is concerned with the now unknown processes of original formation, concentration and esterification of condensed phosphate (diphosphate, pyrophosphate).