Supplementary Figure 10: STEM images used to determine the MPL of low-pH glucagon fibrils.
From: The peptide hormone glucagon forms amyloid fibrils with two coexisting β-strand conformations
a, Stained and b, unstained images of microtubulin. c, Unstained image of glucagon fibrils diluted by 160-fold to isolate individual fibrils. d-f, Representative STEM images used to determine the glucagon MPL. g, Glucagon MPL histogram, showing a broad distribution with a maximum at 40.1 ± 0.5 kDa/nm. The glucagon molecular weight is 3.48 kDa, thus a single cross-β sheet with a 4.8 Å inter-chain spacing has an MPL of 7.25 kDa/nm. Therefore, the maximum MPL value corresponds to 5.5 ± 0.1 cross-β sheets as the predominant fibril species, indicating that three dimers stack in the plane normal to the fibril axis.
