Tryptophan leader peptide
This family consists of the tryptophan (trp) leader peptides. Tryptophan accumulation is the principal event resulting in downregulation of transcription of the structural genes of the trp operon. The leader peptide of the trp operon forms mutually exclusive secondary structures that would either result in the termination of transcription of the trp operon when tryptophan is in plentiful supply or vice versa.
Jiyao W et al.(2023). "The conserved domain database in 2023.",