Fig 1.
Polymorphism of insulin amyloid-like fibrils formed at different pH* values.
FTIR absorption spectra (second derivative spectra in the inset) of fibrils grown in the presence (A), and absence (B) of 5% DMSO (spectra were repeated using different FTIR instruments in different labs, see S1 Fig). AFM images of fibrils prepared in the presence of DMSO at pH*1.6 (C), and pH*2 (D) or in absence of DMSO at pH*1.6 (E), and pH*2 (F). Fibril height measurements are shown in S2 Fig.
Fig 2.
Kinetics of seed-induced aggregation of insulin; followed by ThT fluorescence intensity (A) as maker of fibril formation, and light absorbance at 600 nm (B). Measurements were repeated using 3 batch preparations showing similar results.
Fig 3.
Infrared spectral features determined by the seeding template.
Absorption and second derivative (inset) FTIR spectra.
Fig 4.
Infrared spectra of insulin amyloid-like fibrils formed in normal water (H2O).
Absorption and second derivative (inset) FTIR spectra.
Fig 5.
Proposed scheme of insulin amyloid straining.
Fig 6.
The effect of high insulin concentration (A), and organic cosolvents (B). Absorption and second derivative (inset) FTIR spectra.
Table 1.
Summary of FTIR band positions of insulin amyloid-like fibrils.
Fig 7.
Size distribution of insulin in solution.
DLS measurements were repeated using 3 batch preparations with similar results.