The nonenzymatic template-directed ligation of oligonucleotides

Abstract

The nonenzymatic template-directed ligation of oligonucleotides containing 2′,3′-cyclic phosphate was investigated in the presence of divalent cations. Ligation of the oligonucleotides readily occurred in the presence of Mg2+, Mn2+, Co2+, Zn2+, Pb 2+. Efficacy of the metal ion catalysts inversely correlated with pKa values of the metal-bound water molecules. The intermolecular transesterification reaction yielded at least 95% of 2′,5′- phosphodiester bonds independently on the nature of the metal ion. Relatively high reaction yields (up to 15%) suggest, that RNA fragmentation to oligonucleotides with 2′,3′-cyclic phosphates, followed by reactions of those oligonucleotides could provide a source of new RNA molecules under prebiotic conditions.