Fig. 2: Cryo-EM structures of the lipidic L1 Aβ40 fibril.

a A cross-section of the cryo-EM map, with lipid densities indicated by a yellow arrow. b An overlay of a sharpened high-resolution map and an unsharpened, 4.5 Å low-pass-filtered density shown in gray. The atomic model is shown as sticks. Amino acids that interact with lipids in NMR experiments are colored red (Fig. 3). The close-up view shows areas with pronounced lipid densities. Ring-shaped densities in the cryo-EM cross-sections show the lipid head groups, while rod-shaped densities show the lipid acyl chains. Supplementary Fig. 8a shows the sharpened high-resolution maps at different isosurface levels. c The sharpened high-resolution map (EMDB 21501) with the docked atomic model (PDB 6W0O) of an Aβ40 fibril derived from the brain tissue of an AD patient and amplified by seeded fibril growth³⁷. The arrows indicate proteinaceous densities of unknown sequence³⁷. d Superposition of the lipidic L1 Aβ40 fibril onto the amplified Aβ40 fibril³⁷ from panel (c).