Fig. 4: Isofagomine and noeuromycin binding to TcdB-GTD.
From: Inhibition of Clostridium difficile TcdA and TcdB toxins with transition state analogues
a Double reciprocal plots are shown for isofagomine (top) and noeuromycin (bottom). TcdB-GTD activity was measured in the presence of inhibitor and varying concentrations of UDP-glucose. Isofagomine or noeuromycin; 0 µM, circles; 2 µM isofagomine or 16 µM noeuromycin, triangles; 4 µM isofagomine or 32 µM noeuromycin, diamonds; 8 µM isofagomine or 64 µM noeuromycin Squares. Data points are the mean of experimental data from 3 independent experiments and lines represent the global fit to Eq. 12 for uncompetitive inhibition as described in Methods. b Isothermal titration calorimetry (ITC) analysis of isofagomine (top) or noeuromycin (bottom) binding to TcdB-GTD. c ITC analysis of isofagomine binding to TcdB-GTD in the presence of UDP. d ITC analysis of noeuromycin binding to TcdB-GTD in the presence of UDP. Conditions are provided in Methods. Top panels indicate raw heat data, and bottom panels show integrated heat injections which have been normalized per mole of injectant as a function of molar ratio. Results were best fit to a one-site binding model. Binding parameters represent mean ± SEM for three replicates. Source data are provided as a Source Data file.
