Figure 7.

All FapC proteins can form amyloid fibrils. A, FapC variants were desalted from 8 M GdmCl into MQ water and immediately fibrillated before FTIR analysis was performed on the formed fibrils. The normalized second derivative shown here validates the amyloid nature of the different fibrils. B, representative gel of the supernatants after treatment with FA (here shown for FapC ΔR3 protein). The band around 25 kDa is FapC solubilized by FA. C, percentage of total protein present in supernatant after FA treatment as a function of FA concentration. Gel bands were quantified with ImageJ, normalized to the 100% FA band, and fitted to Equation 8. There is a marked decrease in stability when the number of repeats is reduced.