Fig. 5.
UV–Vis optical binding titration for compound 8h binding to CYP121A1. The left hand panel shows data from a compound 8h titration with CYP121A1 (∼4.7 μM) with the ligand-free spectrum as a thick black line, spectra following progressive additions of 8h as thin solid lines, and the final near-saturated protein spectrum shown as a thick red line. The inset shows overlaid difference spectra generated by the subtraction of the starting spectrum from each consecutive ligand-bound spectrum collected in the titration. The right hand panel shows a plot of compound 8h-induced absorbance change – calculated as the difference between the peak and trough in the difference spectra in the left hand panel, using the same wavelength pair (429 and 392 nm, respectively) throughout. Data were fitted using the Hill equation to give a 8hKD value of 1.2 ± 0.1 μM.