FIG 3.
Electron density maps showing relebactam bound to the active sites of class A β-lactamases. Unbiased omit Fo-Fc electron density maps were calculated with the ligand removed and are shown contoured at 3σ. Gray density is calculated after removal of “intact” relebactam, green density after removal of desulfated relebactam. (A) CTX-M-15 (green, 16-hour soak), (B) L2 (teal, 16 hours), (C) KPC-4 (pink, 1 hour), (D) KPC-2 (yellow, 16 hours), (E) KPC-3 (orange, 16 hours), and (F) KPC-4 (16 hours).