Origin of informational polymers: The concurrent roles of formamide and phosphates

Formamide chemistry provides a unitary system by gathering all of the precursers needed to synthesise pregenetic informational polymers in a single milieu. This is not observed with HCN chemistry. With common catalysts, formamide affords all of the precurser nucleubases, photochemically condenses into acyclo-nucleosides, favours transphosphorylation and enhances micellar aggregation of surfactants. Also, formamide provides a set of physicochemical conditions that thermodynamically favour the polymeric state of nucleotides over the monomers. In the origin-of-informational-polymers scenario, formamide acts in every step, the least characterized being the set of its reactions with phosphates. On this matter, we report two complementary sets of results: 1) the synthesis of prebiotic precursers from formamide, which are catalysed by soluble and mineral phosphates-we observed the formation of rich mixtures that include uracil, 9H-purine, cytosine, dihydrouracil, hypoxanthine, adenosine, urea, parabanic acid, the amino acid N-formylglycine and the peptide-condensing agent carbodiimide; and 2) the protection of ribo- and deoxyribophosphoester bonds by phosphates. The relevance of these effects with respect to the origin of informational polymers is discussed.