5'-RNA SELF-CAPPING FROM GUANOSINE DIPHOSPHATE

A selected RNA (isolate 6) efficiently catalyzes a self-capping reacti on with free GDP, yielding the same 5'-capped structure as is formed b y protein GTP:RNA guanylyltransferase. This unexplored RNA-catalyzed r eaction type involving nucleophilic attack on phosphate by phosphate a dds to the variety of possible postsynthetic RNA-catalyzed RNA modific ations. The selected RNA requires only Ca2+ for activation and has a b road active pH range of 4.5-9.0, The RNA also has a 5'-pyrophosphatase activity.