CATH Classification

Domain Context

CATH Clusters

Superfamily BRCT domain
Functional Family DNA ligase

Enzyme Information

6.5.1.1
DNA ligase (ATP).
based on mapping to UniProt P49917
ATP + (deoxyribonucleotide)(n)-3'-hydroxyl + 5'-phospho- (deoxyribonucleotide)(m) = (deoxyribonucleotide)(n+m) + AMP + diphosphate.
-!- The enzyme catalyzes the ligation of DNA strands with 3'-hydroxyl and 5'-phosphate termini, forming a phosphodiester and sealing certain types of single-strand breaks in duplex DNA. -!- Catalysis occurs by a three-step mechanism, starting with the activation of the enzyme by ATP, forming a phosphoramide bond between adenylate and a lysine residue. -!- The adenylate group is then transferred to the 5'-phosphate terminus of the substrate, forming the capped structure 5'-(5'-diphosphoadenosine)-(DNA). -!- Finally, the enzyme catalyzes a nucleophilic attack of the 3'-OH terminus on the capped terminus, which results in formation of the phosphodiester bond and release of the adenylate. -!- RNA can also act as substrate, to some extent. -!- Cf. EC 6.5.1.2, EC 6.5.1.6 and EC 6.5.1.7.

UniProtKB Entries (1)

Q13426
XRCC4_HUMAN
Homo sapiens
DNA repair protein XRCC4

PDB Structure

PDB 3II6
External Links
Method X-RAY DIFFRACTION
Organism
Primary Citation
Structural and functional interaction between the human DNA repair proteins DNA ligase IV and XRCC4
Wu, P.Y., Frit, P., Meesala, S., Dauvillier, S., Modesti, M., Andres, S.N., Huang, Y., Sekiguchi, J., Calsou, P., Salles, B., Junop, M.S.
MOL.CELL.BIOL.