Fig. 2. Characterization of the structure of SSFH-2 after thermal treatment at 100 °C for different times. (a) SDS-PAGE and (b) native PAGE analyses of thermal-treated SSFH-2. Lane M, protein markers and their corresponding molecular masses; lanes 1, 2, 3, 4, and 5 correspond to SSFH-2 upon treated at 100 °C for 0, 5, 10, 20, and 30 min, respectively. (c) CD spectra and (d) Fluorescence spectra of SSFH-2 upon thermal treatment for 5, 10, 20, and 30 min. (e) TEM image of SSFH-2 at 100 °C for 30 min. Scale bar represent 100 nm. (f) Dynamic light scattering (DLS) analyses of untreated SSFH-2 and upon thermal treatment at 100 °C for 30 min. Conditions: 1.0 μM SSFH-2 in 50 mM MOPS, pH 7.9.