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.
Lu S et al.(2020). "CDD/SPARCLE: the conserved domain database in 2020.",