Fig. 2: Metal complexes of AMA suppress the activity of Ni-dependent enzymes.

A The metal complexed structure, selectivity, and affinity of AMA. The constituents of AMA are labeled l-aspartate (l-Asp) and 2,3-diaminopropionic acid (APA). B Dose-response urease inhibition assays in K. pneumoniae. Urease-dependent pH changes were determined after growth for 24 h at 37 °C in artificial urine. pH is represented by the color scale determined with phenol red. C Dose-response effect of AMA and Zn-AMA on the nucleation of struvite crystals in K. pneumoniae cultures grown in artificial urine. Crystals were examined microscopically in 96-well plates and visually quantified. The inset shows representative images of struvite crystals in the presence and absence of Zn-AMA. The data represent the representative mean of two replicates. D Quantification of planktonic growth and crystal violet-stained biofilms of K. pneumoniae grown in artificial urine and varying concentrations of Zn-AMA. The inset shows representative images of crystal-violet-stained biofilms. Data represent mean ± s.d. of four technical replicates. E ICP-MS quantification of cellular ⁶⁰Ni and ⁶⁶Zn content in K. pneumoniae untreated or treated with 200 μM AMA, or Zn-AMA. Data represent the mean of two biological replicates (F) Dose-response curve of [NiFe]-hydrogenase inhibition in K. pneumoniae grown in LB-glucose for 24 h at 37 °C under anaerobic conditions. Whole-cell hydrogenase assays were performed by adding benzyl viologen (BV) at a final concentration of 1 mg/mL and monitoring its reduction at an absorbance of 630 nm. Data represent the mean of two technical replicates.