Ligases | Thermo Fisher Scientific

Ligases catalyze the joining of nucleic acid molecules enzymatically in an ATP-dependent manner. T4 DNA and RNA ligases are members of a large family of ligases and are derived from the T4 bacteriophage representing the most commonly used ligases in cloning protocols.

Thermo Scientific ligase selection table

	T4 DNA Ligase	T4 RNA Ligase
Applications	Joining dsDNA with cohesive or blunt termini Joining of ds oligonucleotide linkers or adaptors to dsDNA Repairing nicks in duplex DNA, RNA or DNA-RNA hybrids Ligase-mediated RNA detection Site-directed mutagenesis Amplify fragment length polymorphisms	RNA 3'-end labeling with cytidine 3',5'-bis [alpha-³²P] phosphate Joining RNA to RNA Circularization of synthetic oligonucleotides Specific modifications of tRNAs Oligodeoxyribonucleotide ligation to single-stranded cDNAs for 5'-RACE Site-specific generation of composite primers for PCR
Substrate	dsDNA dsRNA dsDNA-RNA hybrids ds poly- and oligonucleotides Oligonucleotides dNTPs/NTPs Phosphorylated proteins	ssDNA ssRNA poly- and oligonucleotides
Reaction catalyzed	ATP-dependent intra- and intermolecular formation of a phosphodiester bond between juxtaposed 5'-phosphate and 3'-hydroxyl termini in duplex DNA or RNA.	ATP-dependent intra- and intermolecular formation of phosphodiester bonds between 5'-phosphate and 3'-hydroxyl termini of poly- and oligonucleotides, ssRNA and ssDNA.

ss – single-stranded
ds – double-stranded
*Although ATP is routinely used as a phosphate donor, CTP, UTP, GTP, dATP, dTTP are equally effective.