Periplasmic binding domain of amidase (AmiC) that belongs to the type I periplasmic binding fold protein family
This group includes the periplasmic binding domain of amidase (AmiC) that belongs to the type I periplasmic binding fold protein family. AmiC controls expression of the amidase operon by the ligand-triggered conformational switch. In the absence of ligand or presence of butyramide (repressor), AmiC (the ligand sensor and negative regulator) adopts an open conformation and inhibits the transcription antitermination function of AmiR by direct protein-protein interaction. In the presence of inducing ligands such as acetamide, AmiC adopts a closed conformation which disrupts a silencing AmiC-AmiR complex and the expression of amidase and other genes of the operon are induced.