This family features the C-terminal region of a number of proteins that bear similarity to the QacR protein (Swiss:P23217), a transcriptional regulator of the TetR family. QacR is able to bind various environmental agents, which include a number of cationic lipophilic compounds, and thus regulate the transcription of QacA (Swiss:P23215), a multidrug efflux pump [1]. The C-terminal region contains the multifaceted, expansive drug-binding pocket, which is composed of several separate, but linked, binding sites [2].

1: QacR is a repressor protein that regulates expression of the Staphylococcus aureus multidrug efflux pump QacA. Grkovic S, Brown MH, Roberts NJ, Paulsen IT, Skurray RA; J Biol Chem 1998;273:18665-18673. PMID:9660841

2: Structural mechanisms of QacR induction and multidrug recognition. Schumacher MA, Miller MC, Grkovic S, Brown MH, Skurray RA, Brennan RG; Science 2001;294:2158-2163. PMID:11739955