Flipping the Switch “On” for Aminoglycoside-Resistance Enzymes: The Mechanism Is Finally Revealed

In a recent issue of Structure, Caldwell et al. (2016) determined crystal structures of APH(2″)-Ia in complex with various combinations of aminoglycosides and nucleosides, which compellingly revealed that the catalytic activity of this resistance enzyme is regulated by a conformational change of the triphosphate of GTP, a mechanism previously unknown for antibiotic kinases. In a recent issue of Structure, Caldwell et al. (2016) determined crystal structures of APH(2″)-Ia in complex with various combinations of aminoglycosides and nucleosides, which compellingly revealed that the catalytic activity of this resistance enzyme is regulated by a conformational change of the triphosphate of GTP, a mechanism previously unknown for antibiotic kinases.