periplasmic ligand-binding domain of putative repressor of the endoglucanase operon and its close homologs
This group includes the ligand-binding domain of putative repressor of the endoglucanase operon from Paenibacillus polymyxa and its close homologs from other bacteria. This group belongs to the LacI-GalR family repressors and are composed of two functional domains: an N-terminal HTH (helix-turn-helix) domain, which is responsible for the DNA-binding specificity, and a C-terminal ligand-binding domain, which is homologous to the sugar-binding domain of ABC-type transport systems that contain the type 1 periplasmic binding protein-like fold. As also observed in the periplasmic binding proteins, the C-terminal domain of the bacterial transcription repressor undergoes a conformational change upon ligand binding which in turn changes the DNA binding.
Jiyao W et al.(2023). "The conserved domain database in 2023.",