 The unfolding followed by differential scanning calorimetry (DSC), circular dichroism (CD), fluorescence resonance energy transfer (FRET) and fluorescence all revealed different apparent melting temperatures.A wavelength-dependent melting temperature was also observed in the CD experiments.The data analyzed with a structure-based statistical mechanical model resulted in a unimodal population distribution at all temperatures, indicating a structurally uncoupled continuous unfolding process.