DNA Ligase I Proteins and Enzymes

DNA ligase 1 catalyzes the joining of double-stranded DNA ends during replication, recombination, and repair. Structurally, DNA ligase 1 is toroidal and encircles nicked DNA substrates. The 9-1-1 complex, a DNA damage checkpoint complex, has been reported to associate with DNA ligase 1 and stimulate ligase activity. Mutations in DNA ligase 1 result in immunodeficiency and increased sensitivity to DNA-damaging agents.