cd10027

Family 1 of Uracil-DNA glycosylase (UDG) enzymes; Uracil-DNA glycosylases (UDGs) are DNA repair enzymes that catalyze the removal of mismatched uracil from DNA to initiate DNA base excision repair pathway. Family 1 enzymes are active against uracil in both ssDNA and dsDNA, and recognize uracil explicitly in an extrahelical conformation via a combination of protein and bound-water interactions. Family 1 enzymes are present in Eubacteria, Eukarya and in some eukaryotic viruses. Members of Family 1 are the most efficient Uracil-DNA glycosylases. Uracil in DNA can arise as a result of mis-incorporation of dUMP residues by DNA polymerase or deamination of cytosine. Uracil mispaired with guanine in DNA is one of the major pro-mutagenic events, causing G:C->A:T mutations. Thus, UDG is an essential enzyme for maintaining the integrity of genetic information. More than five UDG families have been characterized so far; these families share similar overall folds, and common active site motifs. However, they may differ in substrate preferences.