This domain is found at the C-terminal end of the large alpha/beta domain making up various pyrimidine nucleoside phosphorylases. It has slightly different conformations in different members of this family. For example, in pyrimidine nucleoside phosphorylase (PYNP) there is an added three-stranded anti-parallel beta sheet as compared to other members of the family, such as E. coli thymidine phosphorylase (TP). The domain contains an alpha/ beta hammerhead fold and residues in this domain seem to be important in formation of the homodimer.
Jiyao W et al.(2023). "The conserved domain database in 2023.",