Figure 2.

¹⁹F NMR studies on the interaction of OXA‐48 T213C* with avibactam and halide ions. (A) Proposed interaction of avibactam with a class D serine β‐lactamase, showing the carbamylated (green) and uncarbamylated (red) states of the complex. (B) ¹⁹F NMR spectra showing the impact of avibactam on the carbamylation state of OXA‐48 T213C* with and without added sodium bicarbonate. (C) Proposed binding mode of a halide ion in the uncarbamylated active site of the OXA‐48:avibactam complex, based on previous crystallographic work.5 (D) ¹⁹F NMR spectra showing the impact of halide ions on the carbamylation state and ¹⁹F chemical shifts of OXA‐48 T213C*. Note that the addition of sodium fluoride may also affect the pH of the sample. Trifluoroethanol was used as an internal standard for ¹⁹F NMR, and CFCl₃ in CDCl₃ was used as an external standard.