This domain occurs in Streptomyces and related lineages, in proteins with highly variable architectures, typically at or near the C-terminus. Member proteins include at least two from known temperate phage of Streptomyces, including phiSA1p31, for which it is named, from Streptomyces phage phiSASD1.
Jiyao W et al.(2023). "The conserved domain database in 2023.",