Ligand-binding domain of uncharacterized DNA transcription repressors highly similar to that of the repressors specific raffinose (RafR) and alpha-glucosides (AglR) which are members of the LacI-GalR family of bacterial transcription regulators
This group includes the ligand-binding domain of uncharacterized DNA-binding regulatory proteins highly similar to DNA transcription repressors specific for raffinose (RafR) and alpha-glucosides (AglR). Members of this group belong to the LacI-GalR family of bacterial transcription repressors. The LacI-GalR family repressors 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 I 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 affinity of the repressor.
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