Pyrimidine dimer DNA glycosylases excise pyrimidine dimers by hydrolysis of the glycosylic bond of the 5' pyrimidine, followed by the intra-pyrimidine phosphodiester bond. Pyrimidine dimers are the major UV-lesions of DNA.
Endonuclease V removes pyrimidine dimers in DNA induced by UV radiation. The enzyme first associates with the DNA and locates the damaged site by a scanning mechanism. It catalyses 2 reactions to remove DNA pyrimidine dimers: (1)cleavage of glycosidic bond by pyrimidine dimer glycosylase activity, which hydrolyses the N-glycosyl bond of the 5'-thymidine in the thymine dimer site and (2)incision of the phosphodiester bond at the apyrimidinic site via a beta-elimination reaction by the apurinic/apyrimidinic(AP) endonuclease activity.
Defined by 4 residues: THR:C-1 [auth A-2]ARG:C-21 [auth A-22]GLN:C-22 [auth A-23]ARG:C-25 [auth A-26]