This domain of unknown function is found in uncharacterized proteins mainly from bacteria, but it is also found in eukaryotes. Some proteins containing this domain also contain zinc finger C2H2-type domains. There are three conserved motifs: TxI/V, RxFF and FxF, and a conserved W/Y residue at the C-terminal.
Jiyao W et al.(2023). "The conserved domain database in 2023.",