Winged helix-turn-helix (WHTH) DNA-binding domain of the GntR family of transcriptional regulators
This CD represents the winged HTH DNA-binding domain of the GntR (named after the gluconate operon repressor in Bacillus subtilis) family of bacterial transcriptional regulators and their putative homologs found in eukaryota and archaea. The GntR family has over 6000 members distributed among almost all bacterial species, which is comprised of FadR, HutC, MocR, YtrA, AraR, PlmA, and other subfamilies for the regulation of the most varied biological process. The monomeric proteins of the GntR family are characterized by two function domains: a small highly conserved winged helix-turn-helix prokaryotic DNA binding domain in the N-terminus, and a very diverse regulatory ligand-binding domain in the C-terminus for effector-binding/oligomerization, which provides the basis for the subfamily classifications. Binding of the effector to GntR-like transcriptional regulators is presumed to result in a conformational change that regulates the DNA-binding affinity of the repressor. The GntR-like proteins bind as dimers, where each monomer recognizes a half-site of 2-fold symmetric DNA sequences.