This model represents a clade within the uracil-DNA glycosylase superfamily. Among characterized proteins, it most closely resembles the Thermus thermophilus uracil-DNA glycosylase TTUDGA, which acts uracil (deamidated cytosine) in both single-stranded DNA and U/G pairs of double-stranded DNA. This domain may occur either as a stand-alone protein or as the C-terminal domain of a fusion with another domain that always pairs with a particular radical-SAM family protein.