A novel uracil-DNA glycosylase with broad substrate specificity and an unusual active site.

ABSTRACT: Uracil-DNA glycosylases (UDGs) catalyse the removal of uracil by flipping it out of the double helix into their binding pockets, where the glycosidic bond is hydrolysed by a water molecule activated by a polar amino acid. Interestingly, the four known UDG families differ in their active site make-up. The activating residues in UNG and SMUG enzymes are aspartates, thermostable UDGs resemble UNG-type enzymes, but carry glutamate rather than aspartate residues in their active sites, and the less active MUG/TDG enzymes contain an active site asparagine. We now describe the first member of a fifth UDG family, Pa-UDGb from the hyperthermophilic crenarchaeon Pyrobaculum aerophilum, the active site of which lacks the polar residue that was hitherto thought to be essential for catalysis. Moreover,

SUBMITTER: Sartori AA 

PROVIDER: S-EPMC126064 | biostudies-literature | 2002 Jun

REPOSITORIES: biostudies-literature