Nucleoside phosphorylation by phosphate minerals

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 103 h. At high concentrations, soluble non-mineral phosphate donors (KH2PO4 or 5′-CMP) afford 2′- and 2′:3′-cyclic AMP in addition to 5′-and 3′-AMP. The phosphate minerals analyzed were Herderite Ca[BePO4F], Hureaulite Mn2+5(PO3(OH)2(PO4) 2(H2O)4, Libethenite Cu2+2(PO4)(OH), Pyromorphite Pb5(PO 4)3Cl, Turquoise Cu2+Al6(PO 4)4(OH)8(H2O)4, Fluorapatite Ca5(PO4)3F, Hydroxylapatite Ca5(PO4)3OH, Vivianite Fe2+3(PO4)2(H2O)8, Cornetite Cu2+3(PO4)(OH)3, Pseudomalachite Cu2+5(PO4)2(OH)4, Reichenbachite Cu2+5(PO4)2(OH) 4, and Ludjibaite Cu2+5(PO4) 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 β-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 (ΔG°') problem, the major obstacle for polymerizations in the liquid phase in plausible prebiotic scenarios. © 2007 by The American Society for Biochemistry and Molecular Biology, Inc.