Figure 3.

Effects of pH on the intrinsic fluorescence and on far UV CD spectra of the Solfolobus solfataricus recombinant wild type (wt) amidase and the Y41C mutant. Fluorescence emission spectra (A, C) were recorded with the excitation wavelength at 295 nm. Far UV CD spectra were recorded in a 0.1 cm path-length quartz cuvette. All spectra were recorded with 0.1 mg ml^–1 protein concentrations at 20 °C after overnight incubation of the wt (A, B) and the Y41C mutant (C, D) at pH 8.0 (20 mM sodium phosphate, solid line) and pH 5.0 (20 mM sodium citrate, dotted line).