Deciphering the molecular basis of multidrug recognition: crystal structures of the Staphylococcus aureus multidrug binding transcription regulator QacR.

Multidrug transporters and their transcriptional regulators are key components of bacterial multidrug resistance (MDR). How these multidrug binding proteins can recognize such chemically disparate compounds represents a fascinating question from a structural standpoint and an important question in future drug development efforts. The Staphylococcus aureus multidrug binding regulator, QacR, is soluble and recognizes an especially wide range of structurally dissimilar compounds, properties making it an ideal model system for deciphering the molecular basis of multidrug recognition. Recent structures of QacR have afforded the first view of any MDR protein bound to multiple drugs, revealing key structural features of multidrug recognition, including a multisite binding pocket.