This model describes a family of radical SAM/SPASM enzymes largely from the deltaproteobacteria. The family is most closely related to radical SAM enzyme family regularly in archaea in the vicinity of tungsten-containing oxidoreductases. A single member of the family in archaea may correspond to multiple tungsten enzymes, e.g. five in Pyrococcus furiosus. Therefore, the lack of a conserved gene neighborhood for members of this family in deltaprotebacteria suggests members may be involved in the maturation of multiple metalloenzymes.
Jiyao W et al.(2023). "The conserved domain database in 2023.",