This family of proteins, predominantly found in Bacteria, are involved in the desulfuration of 2-thiouracil into uracil in the 2-thiouridine degradation pathway. It has been demonstrated that these proteins contain a Fe-S cluster required for their activity [1].

1: A gene encoding a DUF523 domain protein is involved in the conversion of 2-thiouracil into uracil. Aucynaite A, Rutkiene R, Gasparaviciute R, Meskys R, Urbonavicius J; Environ Microbiol Rep. 2018;10:49-56. PMID:29194984