Fig. 1. Mesoscopic analysis of reversible and irreversible amyloids of human lysozyme and HEWL.

AFM images (a) of flexible (reversible) and rigid (irreversible) fibrils from human lysozyme and HEWL. The height distribution (b) and shape fluctuations (c) of flexible (left) and rigid (right) fibrils of HEWL (upper) and human (lower) lysozyme. The rigidity of the reversible and irreversible fibrils is measured by the persistence length (L_p) via mean square deviation against the secant length³⁵ (d) and confirmed via mean square end-to-end distance³⁶ (e); both indicate the extreme flexibility of reversible fibrils, which is two orders of magnitude lower than that of rigid irreversible fibrils. The upper and lower parts in the panels (b–d) refer to HEWL and human lysozyme, respectively. More than 700 fibrils from each condition from at least three independent experiments were analyzed in the statistical analysis. N  =  3 replicates. The box plots in panel b are shown as median value with box range of 25–75% and the outlier whiskers, and the bar plots in panel e are shown as mean values with standard deviation.