Conformational change of the AcrR regulator reveals a possible mechanism of induction

The Escherichia coli AcrR multidrug-binding protein represses transcription of acrAB and is induced by many structurally unrelated cytotoxic compounds. The crystal structure of AcrR in space group P222₁ has been reported previously. This P222₁ structure has provided direct information about the multidrug-binding site and important residues for drug recognition. Here, a crystal structure of this regulator in space group P3₁ is presented. Comparison of the two AcrR structures reveals possible mechanisms of ligand binding and AcrR regulation.