Fig. 2.

Cryo-EM structures of PHFs and SFs from the frontal cortex of AD cases 1, 2, 3, and 16. All structures show identical pairs of C-shaped protofilaments and the same inter-protofilament packing in PHFs and SFs. Cases 1, 2, and 3 had sporadic AD, whereas case 16 had inherited AD (mutation V717F in APP). The filament structures of case 1 are from (14); the structures from cases 2, 3, and 16 are first described here. All cases had a majority of PHFs and a minority of SFs. Yellow arrows indicate the extra densities, which are present in PHFs and SFs from all four cases, bordering the solvent-exposed side chains of R349 and K375, and of H362 and K369. Scale bar, 50 Å