Template-directed synthesis with 2-aminoadenosine.

A random copolymer, poly(CA), containing approximately equal amounts of cytidine (C) and adenosine (A), when incubated with a mixture of guanosine-5'-phosphoro-(2-methylimidazole) (2-MeImpG) and uridine-5'-phosphoro-(2-methylimidazole) (2-MeImpU), facilitates the incorporation of uridine (U) into oligomeric products with low efficiency. If 2-aminoadenosine (aA) is substituted for adenosine in the template, U is incorporated into the products with much higher efficiency. Random copolymers of C and U act as templates for the efficient synthesis of oligomers from 2-MeImpG and 2-MeImpA only if the concentration of substrates is relatively high (0.1 M). The substitution of 2-MeImpA permits the reaction to occur with much lower substrate concentrations. This effect is most prominent for template containing large amounts of U.