{"rfam": {"acc": "RF00442", "id": "Guanidine-I", "description": "Guanidine-I riboswitch aptamer", "comment": "This family represents a conserved RNA structure found upstream of the ykkC and yxkD genes in Bacillus subtilis and related genes in other bacteria. The function of this family is unclear although it has been suggested that it may function to switch on efflux pumps and detoxification systems in response to harmful environmental molecules [1]. The Thermoanaerobacter tengcongensis sequence EMBL:AE013027 overlaps with Rfam:RF00167 suggesting that the two riboswitches may work in conjunction to regulate the upstream gene which codes for Swiss:Q8RC62, a member of Pfam:PF00860 (Moxon SJ, pers. obs.). Nelson [2] showed that this riboswitch senses and responds to guanidine and it was renamed Guanidine-I riboswitch. Furthermore, they demonstrated that bacteria are capable of endogenously producing guanidine and the riboswitch controls genes whose products are involved in modification or pumping out guanidine as a toxic compound from bacteria. Crystal structures of the riboswitch bound to the ligand have also been determined in PDB 5T83, 5U3G and 7MLW [3][4].", "curation": {"author": "Moxon SJ, Ontiveros-Palacios N", "seed_source": "Barrick JE, Breaker RR", "num_seed": 100, "num_full": 1509, "num_species": 1281, "type": "Cis-reg; riboswitch;", "structure_source": "Predicted; Barrick JE, Breaker RR"}, "cm": {"build_command": "cmbuild -F CM SEED", "calibrate_command": "cmcalibrate --mpi CM", "search_command": "cmsearch --cpu 4 --verbose --nohmmonly -T 30.00 -Z 2958934 CM SEQDB", "cutoffs": {"gathering": 63.0, "trusted": 63.0, "noise": 62.9}}, "release": {"date": "2026-01-16", "number": "15.1"}, "clan": {"acc": null, "id": null}}}