Nucleoside Phosphorylation by Phosphate Minerals

Giovanna Costanzo,Raffaele Saladino,Claudia Crestini,Fabiana Ciciriello,Ernesto Di Mauro

doi:10.1074/jbc.m611346200

Abstract

In the presence of formamide, crystal phosphate minerals may act as phosphate donors to nucleosides, yielding both 5'- and, to a lesser extent, 3'-phosphorylated forms. With the mineral Libethenite the formation of 5'-AMP can be as high as 6% of the adenosine input and last for at least 10(3) h. At high concentrations, soluble non-mineral phosphate donors (KH(2)PO(4) or 5'-CMP) afford 2'- and 2':3'-cyclic AMP in addition to 5'-and 3'-AMP. The phosphate minerals analyzed were Herderite Ca[BePO(4)F], Hureaulite Mn(2+)(5)(PO(3)(OH)(2)(PO(4))(2)(H(2)O)(4), Libethenite Cu(2+)(2)(PO(4))(OH), Pyromorphite Pb(5)(PO(4))(3)Cl, Turquoise Cu(2+)Al(6)(PO(4))(4)(OH)(8)(H(2)O)(4), Fluorapatite Ca(5)(PO(4))(3)F, Hydroxylapatite Ca(5)(PO(4))(3)OH, Vivianite Fe(2+)(3)(PO(4))(2)(H(2)O)(8), Cornetite Cu(2+)(3)(PO(4))(OH)(3), Pseudomalachite Cu(2+)(5)(PO(4))(2)(OH)(4), Reichenbachite Cu(2+)(5)(PO(4))(2)(OH)(4), and Ludjibaite Cu(2+)(5)(PO(4))(2)(OH)(4)). Based on their behavior in the formamide-driven nucleoside phosphorylation reaction, these minerals can be characterized as: 1) inactive, 2) low level phosphorylating agents, or 3) active phosphorylating agents. Instances were detected (Libethenite and Hydroxylapatite) in which phosphorylation occurs on the mineral surface, followed by release of the phosphorylated compounds. Libethenite and Cornetite markedly protect the beta-glycosidic bond. Thus, activated nucleic monomers can form in a liquid non-aqueous environment in conditions compatible with the thermodynamics of polymerization, providing a solution to the standard-state Gibbs free energy change (DeltaG degrees ') problem, the major obstacle for polymerizations in the liquid phase in plausible prebiotic scenarios.

Highlights

In the polymerization process of nucleic acids extant organisms activate the monomers by converting them to phosphorylated derivatives and utilize the favorable free energy of phosphate hydrolysis to drive the reaction
In the presence of formamide, crystal phosphate minerals may act as phosphate donors to nucleosides, yielding both 5؅and, to a lesser extent, 3؅-phosphorylated forms
Activated nucleic monomers can form in a liquid non-aqueous environment in conditions compatible with the thermodynamics of polymerization, providing a solution to the standard-state Gibbs free energy change (⌬G°’) problem, the major obstacle for polymerizations in the liquid phase in plausible prebiotic scenarios

Summary

Introduction

In the polymerization process of nucleic acids extant organisms activate the monomers by converting them to phosphorylated derivatives and utilize the favorable free energy of phosphate hydrolysis to drive the reaction. Does this present day process mimic spontaneously occurring prebiotic reactions, representing a sort of biochemiomimesis descending from ancient pathways, or should it be considered a fully novel cellular invention?. The alternative offered by phosphorylation in organic solvents, notably in formamide, was described in a series of pioneering studies by Schoffstal (9 –12) Building on these latter observations and on the large availability of phosphates in mineral form, we report the efficient phosphorylation of nucleosides occurring in formamide on numerous phosphate minerals. Abiotic Nucleoside Phosphorylation uid, non-aqueous environment in the presence of phosphate minerals in conditions compatible with the thermodynamics of polymerization

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Results

Conclusion