Thermal denaturation of Josephin stability mutants. Thermal denaturation was followed at 280 nm using near-UV CD. The temperature was increased by 1°C min−1 in a stoppered cuvette with a sample concentration of 1 mg mL−1. Representative traces are shown for (A) Josephin, (B) ataxin-3(Q15), and (C) ataxin-3(Q64) with wild-type (black), R103G (blue), S81A (green), R103G S81A (purple), and L169H (red).