Thermal melts of CPG2 and its circular permutants. (A) Normalized thermal melt data, where the initial mean residue ellipticity ([θ]MR) at 217 nm is set to 0, and the final [θ]MR is set to 1. Prior to normalization, [θ]MR is in units of deg cm2 dmol−1. Data points show the individual readings, and a fitting curve is drawn as a line for each data set. (B) First derivative of the fitting curve shown in (A). The maximum, indicating the melting temperature, is indicated using a dashed, vertical line.