Polynucleotide ligase-catalyzed joining of deoxyribo-oligonucleotides on ribopolynucleotide templates and of ribo-oligonucleotides on deoxyribopolynucleotide templates.

T4 polynucleotide ligase efficiently catalyzes the head-to-tail joining of the ribo-oligoadenylates, r-(pA)(8) and r-(pA)(10), in the presence of high molecular weight deoxypolythymidylate. The enzyme also catalyzes the joining of deoxy-oligothymidylates, e.g., d-(pT)(10), in the presence of ribopolyadenylate. The enzyme failed to bring about the joining of r-(pA)(10) when poly r-U was used as the template, although a slow formation of the expected activated intermediate from r-(pA)(10) was detected.