Some proteins with this domain toward the C-terminus have an N-terminal region with a radical SAM domain (pfam04055) and a SPASM domain (TIGR04085), a combination frequently associated with peptide modification. All seed alignment members, and all family members that are not fused to a radical SAM domain, have a motif HEXXH that suggests metalloprotease activity. A role in peptide or protein maturation is suggested.
Jiyao W et al.(2023). "The conserved domain database in 2023.",