T3 DNA ligase

T3 DNA Ligase is an ATP-dependent dsDNA ligase derived from bacteriophage T3 and recombinantly expressed in E. coli. It catalyzes the formation of phosphodiester bonds between adjacent 5′-phosphate and 3′-hydroxyl termini in double-stranded DNA (dsDNA), with higher efficiency for A/T overhangs than C/G overhangs. The enzyme efficiently ligates dsDNA with either sticky or blunt ends, repairs nicks in dsDNA, and seals nicks in DNA/RNA hybrids containing an intact DNA strand. Consequently, T3 DNA Ligase can be used to generate DNA-RNA chimeras and to ligate RNA fragments using a DNA template.

Similar to T4 DNA Ligase, the addition of PEG 6000 significantly enhances blunt-end ligation efficiency. T3 DNA Ligase exhibits twice the salt tolerance of T4 DNA Ligase, retaining >95% activity in 1.0 M NaCl or KCl, making it an ideal choice for ligation under high-salt conditions.