Figure 6. Heat-induced denaturation of the PD proteins is preceded by flavin release.

(a) Melting curves of HsCoaC and Hal3^PD (H), Vhs3^PD (V), Hal3^PD/Cab3^PD (H + C), Vhs3^PD/Cab3^PD (V + C), and co-expressed Hal3^PD/Vhs3^PD/Cab3^PD (H + V + C) as determined by the changes in the proteins’ molar elipticity at 222 nm. The curves represent the fraction folded protein as a function of temperature. (b) First derivative plots of the melting curves shown in panel a, smoothed using the standard settings in SigmaPlot 11. (c) Plots of changes in the molar elipticity measured for the indicated proteins at 320 nm as a function of temperature; the curves represent the best fits of the Gibbs-Helmholtz equation to the data (see Methods for details).