T4 RNA Ligase 1 is an ATP-dependent enzyme that catalyzes the formation of phosphodiester bonds between the 5´-phosphate and 3´-hydroxyl termini of single-stranded RNA, single-stranded DNA, RNA and mononucleotides, in either intermolecular or intramolecular reactions.

T4 RNA Ligase 1 exhibits the highest ligation efficiency for RNA-to-RNA junctions, moderate efficiency for single-stranded DNA to single-stranded RNA, and very low efficiency for single-stranded DNA-to-DNA ligation. For DNA-RNA ligation, the reaction is more efficient when the DNA provides the 5´ phosphate and the RNA provides the 3´ hydroxyl; the reverse orientation (RNA 5´ phosphate and DNA 3´ hydroxyl) is less efficient.

The enzyme can ligate RNA molecules intermolecularly, as well as circularize RNA molecules (minimum length ~8 bases). It can also ligate RNA to mononucleotides, commonly used for 3′-end labeling of RNA. Additionally, it can circularize DNA, for example cDNA circularization in 5´ RACE applications.

Applications