Geochemical Sources and Availability of Amidophosphates on the Early Earth

Phosphorylation of (pre)biotically relevant molecules in aqueous medium has recently been demonstrated using water-soluble diamidophosphate (DAP). Questions arise relating to the prebiotic availability of DAP and other amidophosphosphorus species on the early earth. Herein, we demonstrate that DAP and other amino-derivatives of phosphates/phosphite are generated when Fe3P (proxy for mineral schreibersite), condensed phosphates, and reduced oxidation state phosphorus compounds, which could have been available on early earth, are exposed to aqueous ammonia solutions. DAP is shown to remain in aqueous solution under conditions where phosphate is precipitated out by divalent metals. These results show that nitrogenated analogues of phosphate and reduced phosphite species can be produced and remain in solution, overcoming the thermodynamic barrier for phosphorylation in water, increasing the possibility that abiotic phosphorylation reactions occurred in aqueous environments on early earth

On the Origin of Phosphorylated Biomolecules

Phosphorus is a key element in biology, serving in cellular replication, metabolism, and structure. The versatility of phosphorus in biology is due to several unique chemical characteristics that rely on its electronic structure and geochemical abundance. The formation of phosphorylated biomolecules and their activated precursors have hence been a major focus of prebiotic syntheses for the past 50 years. This chapter highlights the basic chemical and physical features that make phosphorus chemicals so valuable within contemporary biochemistry, the putative prebiotic routes to phosphorylated biomolecules, and a growing role for reduced oxidation state phosphorus compounds, including those derived from meteorites, in the development of life on the Earth. We distinguish three primary forms of biological phosphates that form an energetic hierarchy: (i) stable phosphorylated biomolecules that are unreactive and in which the P provides a structural or binding handle; (ii) energetic condensed phosphates including ATP which store metabolic energy; and (iii) reactive phosphorylated biomolecules which are generated during metabolism and transfer phosphates and energy to condensed phosphates for energy storage. We suggest here that: (1) precursors to modern biologic phosphates likely included reduced oxidation state phosphorus compounds; (2) ATP as the main metabolic energy transfer agent likely arose well after the origin of life, and was likely co-opted from its role as a RNA building block into its metabolic role