DNA ligase activity Reactome:R-HSA-5649734 Reactome:R-HSA-6782227 GO:0003909 Reactome:R-HSA-5687675 Reactome:R-HSA-5686663 Reactome:R-HSA-175258 Reactome:R-HSA-174456 Reactome:R-HSA-5651805 Reactome:R-HSA-5690997 Reactome:R-HSA-5693604 Reactome:R-HSA-73931 Reactome:R-HSA-5651789 Reactome:R-HSA-69173 Reactome:R-HSA-5358592 molecular_function 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+. ligase activity, forming phosphoric ester bonds catalytic activity, acting on DNA