Catalysis of the formation of a phosphodiester bond between the 3'-hydroxyl group at the end of one DNA chain and the 5'-phosphate group at the end of another. This reaction requires an energy source such as ATP or NAD+.
Synonyms:
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reactome:R-HSA-174456 "Joining of adjacent Okazaki fragments of the C-strand"; reactome:R-HSA-175258 "2-LTR formation due to circularization of viral DNA"; reactome:R-HSA-5358592 "DNA ligase I ligates single stranded nick in double stranded DNA"; reactome:R-HSA-5649734 "LIG3 ligates NEIL1,NEIL2-generated single strand break"; reactome:R-HSA-5651789 "LIG1 bound to POLB ligates SSB"; reactome:R-HSA-5651805 "LIG1 bound to APEX1 and PCNA ligates SSB"; reactome:R-HSA-5687675 "LIG3 ligates remaining SSBs in MMEJ"; reactome:R-HSA-5690997 "Ligation of newly synthesized repair patch to incised DNA in GG-NER"; reactome:R-HSA-5693604 "XRCC4:LIG4 ligates DNA DSB ends during NHEJ"; reactome:R-HSA-6782227 "Ligation of newly synthesized repair patch to incised DNA in TC-NER"; reactome:R-HSA-69173 "Joining of adjacent Okazaki fragments"; reactome:R-HSA-73931 "LIG3-mediated DNA ligation via the single-nucleotide replacement pathway"