ID   6.5.1.6
DE   DNA ligase (ATP or NAD(+)).
CA   (1) ATP + (deoxyribonucleotide)n-3'-hydroxyl + 5'-phospho-
CA   (deoxyribonucleotide)m = (deoxyribonucleotide)n+m + AMP + diphosphate.
CA   (2) NAD(+) + (deoxyribonucleotide)n-3'-hydroxyl + 5'-phospho-
CA   (deoxyribonucleotide)m = (deoxyribonucleotide)n+m + AMP + beta-
CA   nicotinamide D-nucleotide.
CC   -!- The enzymes from the archaea Thermococcus fumicolans and Thermococcus
CC       onnurineus show high activity with either ATP or NAD(+),
CC       and significantly lower activity with TTP, GTP, and CTP.
CC   -!- The enzyme catalyzes the ligation of DNA strands with 3'-hydroxyl and
CC       5'-phosphate termini, forming a phosphodiester and sealing certain
CC       types of single-strand breaks in duplex DNA.
CC   -!- Catalysis occurs by a three-step mechanism, starting with the
CC       activation of the enzyme by ATP or NAD(+), forming a phosphoramide
CC       bond between adenylate and a lysine residue.
CC   -!- The adenylate group is then transferred to the 5'-phosphate terminus
CC       of the substrate, forming the capped structure
CC       5'-(5'-diphosphoadenosine)-[DNA].
CC   -!- Finally, the enzyme catalyzes a nucleophilic attack of the 3'-OH
CC       terminus on the capped terminus, which results in formation of the
CC       phosphodiester bond and release of the adenylate.
CC   -!- Different from EC 6.5.1.1, EC 6.5.1.2 and EC 6.5.1.7.
DR   Q9HH07, DNLI_THEFM ;  Q9HHC4, DNLI_THEKO ;  B6YTR4, DNLI_THEON ;
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