Formation of a 2'-phosphomonoester, 3',5'-phosphodiester linkage by a novel RNA ligase in wheat germ.

Extracts of wheat germ contain an RNA ligase activity that catalyses the conversation of linear polyribonucleotides into covalently closed circles. The newly formed 3',5'-phosphodiester bridge is resistant to alkali and a number of ribonucleases. This unusual stability is due to the presence of a phosphoryl group esterified to the 2'-position of the 3'-nucleotide joined. This is the first demonstration of an RNA ligase in higher plants and of a natural 2'-phosphomonoester, 3',5'-phosphodiester linkage.