InterPro domain: IPR013840

DNA ligase (polydeoxyribonucleotide synthase) is the enzyme that joins two DNA fragments by catalyzing the formation of an internucleotide ester bond between phosphate and deoxyribose. It is active during DNA replication, DNA repair and DNA recombination. There are two forms of DNA ligase: one requires ATP ( 6.5.1.1 ), the other NAD ( 6.5.1.2 ).

This entry represents the N-terminal region of NAD-dependent bacterial DNA ligases. They are proteins of about 75 to 85 Kd whose sequence is well conserved [ 1 , 2 ]. They also show similarity to yicF, an Escherichia coli hypothetical protein of 63 Kd. The region described by this model covers the adenylation, OB-fold and zinc-finger domains of these enzymes [ 3 , 4 ].

1. Cloning and molecular characterization of the DNA ligase gene (lig) from Zymomonas mobilis. FEMS Microbiol. Lett. 75, 19-26
2. Guanylate kinase of Escherichia coli K-12. J. Biol. Chem. 268, 14316-21
3. Crystal structure of NAD(+)-dependent DNA ligase: modular architecture and functional implications. EMBO J. 19, 1119-29
4. Structure of the adenylation domain of an NAD+-dependent DNA ligase. Structure 7, 35-42