Fig. 2.
Monitoring urea- and temperature-mediated unfolding of KatG from Magnaporthe grisea by heme electronic circular dichroism (ECD) spectroscopy. (A) Soret circular dichroism spectra of 6 μM native Magnaporthe grisea KatG (gray line) incubated with various concentration of urea (0.5, 1, 1.25, 1.5, 1.75, 2, 2.25 and 6 M) for 18 h at 25 °C. Panel (B) shows the changes in ECD spectra during the thermal transition of Magnaporthe grisea KatG (8.7 μM) in 5 mM phosphate buffer, pH 7.0, containing 0.5 M urea. The ECD spectrum at 25 °C is depicted in gray. Panel (C) shows the change in CD ellipticity at 412 nm as a function of denaturant concentration for MagKatG. Inset shows the change in standard free enthalpy with urea concentration. Panel (D) along with the insets shows the loss of CD ellipticity at 412 nm in MagKatG1 with increasing temperature and the corresponding Van’t Hoff plot.
