Members of this protein family are cysteine-rich small peptides, about 52 amino acids long, that are proposed targets for modification by a radical SAM enzyme. Known occurrences are as tandem gene pairs Fibrobacter succinogenes subsp. succinogenes S85 (missed gene calls) and in Ruminococcus albus 8.
Jiyao W et al.(2023). "The conserved domain database in 2023.",