T4 DNA Ligase

• T4 DNA ligase is a highly efficient enzyme derived from the T4 bacteriophage that catalyzes the formation of phosphodiester bonds between adjacent nucleotides in double-stranded DNA (dsDNA). It plays a critical role in molecular biology and genetic engineering by enabling the joining of DNA fragments, particularly during cloning, DNA repair studies, and recombinant DNA technologies.
• The enzyme specifically seals nicks in the DNA backbone by covalently linking the 3′ hydroxyl (OH) end of one nucleotide to the 5′ phosphate (PO₄) end of another. T4 DNA ligase requires ATP as a cofactor to activate the ligation process. It exhibits high activity at room temperature or 16–25°C, though reactions can also be performed at 4°C (for overnight ligations) or at 37°C for certain rapid protocols.
• T4 DNA ligase is unique in its ability to ligate both sticky (cohesive) and blunt ends, making it particularly valuable for a wide range of DNA manipulation tasks. It is often used to ligate DNA inserts into plasmid vectors, circularize linear DNA, and repair single-stranded breaks during molecular cloning. Its ability to join blunt-ended DNA fragments is especially useful, although such reactions are generally less efficient than those involving cohesive ends and may require higher enzyme concentrations or longer incubation.
• In addition to DNA–DNA ligation, T4 DNA ligase can also join RNA–DNA hybrids or RNA molecules under certain conditions, though with reduced efficiency. This has applications in specialized techniques like adapter ligation in RNA-seq library preparation.
• Due to its broad substrate compatibility and reliable activity, T4 DNA ligase is considered a cornerstone enzyme in molecular biology labs. It has facilitated the development of recombinant DNA technologies and continues to be a critical tool for genetic engineering, synthetic biology, and DNA assembly workflows.

Suppliers:

From ThermoFisherScientific
Product details: T4 DNA Ligase (5 U/µL)
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From NEB
Product details: T4 DNA Ligase
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From TaKaRa
Product details: T4 DNA Ligase
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From Promega
Product details: T4 DNA Ligase
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From Sigma-Aldrich
Product details: DNA Ligase from T4-infected Escherichia coli
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