Fig. 3.

Thermal denaturation of WT Ngb and mutants. The spectra for the ferric heme species determined at increasing temperatures are shown. The initial spectrum (20 °C) is denoted by a thick black line, and the final spectrum (approx. 98 °C) is denoted by a thick red line. Intermediate spectra are shown as thin black lines. The insets show the changes in the Soret peak absorbance with the temperature and the fit of the absorbance changes to the Santoro−Bolen equation (red lines).