Pyrophosphate formation as the most efficient condensation reaction of activated nucleotides.

When an oligonucleotide primer pG10 is incubated with the nucleotide analogue 9-[3-hydroxy-2-(hydroxymethyl)prop-1-yl] guanine diphosphate (pGp, I) in the presence of poly(C), addition of the monomer occurs almost exclusively at the 5'-terminal phosphate rather than the 3'-terminal cis-glycol. The implications of this finding in the context of prebiotic condensation reactions are discussed.