Fig. 3
Aβ20–34, isoAsp23 structure contains an altered protofilament interface. a Representative single crystal electron diffraction pattern of Aβ20–34 with resolution rings obtained during microcrystal electron diffraction (MicroED) data collection. Left inset shows the diffracting crystal (lower left scale bar represents 1 μm). Right inset shows light microscopic image of microcrystal sediment in a 1.6-mL microfuge tube (scale bar represents 3 mm). b One layer of the Aβ20–34 crystal structure viewed down the fibril axis highlighting two distinct steric zipper interfaces. Interface distances are labeled (center circle indicates fibril axis). Waters are represented by red crosses. The 2Fo − Fc density is shown as a gray mesh at 2σ on the center protofilament. The Asp23 residue is outlined in magenta and shown by the red arrow. c Three layers of the Aβ20–34 structure viewed perpendicular to the fibril axis (indicated by arrows; Left panel—interface A, right panel–L-Asp interface B). d Representative single crystal electron diffraction pattern of Aβ20–34, isoAsp23 with resolution rings obtained during MicroED data collection. Left inset shows the diffracting crystal (lower left scale bar represents 1 μm). Right inset shows a light microscopic image of microcrystal sediment in a 1.6-mL microfuge tube (scale bar represents 3 mm). e One layer of the Aβ20–34, isoAsp23 crystal structure viewed down the fibril axis highlighting two distinct steric zipper interfaces. Interface distances are labeled (center circle indicates fibril axis). Waters are represented by red crosses. The 2Fo − Fc density is shown as a gray mesh at 2σ on the center protofilament. The L-isoAsp23 residue is outlined in magenta and shown by the red arrow. f, Three layers of the Aβ20–34, isoAsp23 structure viewed perpendicular to the fibril axis (indicated by arrows; Left panel—interface A, right panel—L-isoAsp interface B)
