A cryo–electron microscopy method called MicroED (micro–electron diffraction) has been used to reveal the core structures of several amyloid fibrils. With this technique, Gallagher-Jones et al. determined a 0.72-Å-resolution structure of fibrils formed by a peptide at the core of the infectious scrapie form of mammalian prion protein (proto-PrPSc). Like the full PrPSc, the fibril is characterized by unusually high stability. The high-resolution structure shows β-strands that stack into β-sheets, with sheets pairing front-to-back to form fibrils. A network of hydrogen bonds within and between β-strands forms “polar clasps,” which are shielded by aromatic residues that stack in the fibrils.
Nat. Struct. Mol. Biol. 25, 131 (2018).
