Template-directed oligomerization of 3-isoadenosine 5'-phosphate.

Template-directed oligomerization of an activated derivative of 3-isoadenosine 5'-phosphate (piA) on polyuridylic acid [poly(U)] was studied. The reaction of ImpiA is more efficient than the corresponding reaction of ImpA, and produces 3'-5'-linked oligomers while the reaction of ImpA gives only 2'-5'-linked oligomers. The base pairing between piA and poly(U) in this system is probably of the Hoogsteen type (involving the 6-amino group and N7 of 3-isoadenosine) rather than of the Watson-Crick type.