The enzyme DNA ligase chemically bonds together two DNA strands and removes nicks in a DNA duplex.
This enzyme is catalyzer for the formation of a phosphodiester bonds. Three major processes in which DNA ligases are involved are:
• DNA replication- after the RNA primers are removed, the remained nicks are replaced by the enzyme DNA ligase
• DNA repair-usually single-strand breaks are repaired by DNA ligase and complementary strand of the double helix is used as a template
• Recombination of DNA in experiments- in gene cloning, DNA ligase joins DNA molecules together to form recombinant DNA.