Structural properties of WT and L260P mini-spectrins. (A) Representative differential scanning calorimetry (DSC) scans of WT and L260P tetramers. DSC analysis was performed in 10 mM sodium phosphate, 130 mM NaCl, and 1 mM Tris(2-carboxyethyl)-phosphine hydrochloride (TCEP) pH 7.4 using a scan rate of 30°C/h over the temperature range of 20-90°C at a protein concentration of 0.5 mg/mL. (B) Representative circular dichroism (CD) results from WT and L260P tetramer. CD analysis was performed in 10 mM sodium phosphate, 130 mM sodium fluoride, and 0.1 mM TCEP pH 7.4 using a protein concentration of 0.16 mg/mL. (C) CD analysis of WT and L260P dimers at 0.18 mg/mL. (D) A total of 100 pmol mini-spectrin tetramer injected immediately after isolation at 4°C in 10 mM sodium phosphate, 130 mM sodium chloride, 0.1 mM EDTA, 0.15 mM phenylmethylsulfonyl fluoride, 1 mM TCEP pH 7.0 (upper panel), and after 90 minutes’ incubation at 37°C (lower panel). (E) A total of 100 pmol mini-spectrin dimers injected immediately after isolation at 4°C (upper panel) and after 90 minutes’ incubation at 37°C (lower panel).