Template-directed synthesis of oligoadenylates catalyzed by Pb2+ ions

The Pb2+ ion is an effective catalyst for the template-directed condensation of ImpA on poly(U). This reaction generates up to 35% of oligomers 5 or more units long. Furthermore, the product is predominantly 3'-5'-linked (75%) unlike that from the uncatalyzed reaction which is more than 90% 2'-5'-linked. The significance of metal-ion catalysis for prebiotic polynucleotide formation is discussed.