Fig. 3

Cryo-EM cross-sections and structures of tau filaments from SSPE. a Cross-sections through the cryo-EM reconstructions, perpendicular to the helical thickness and with a projected thickness of approximately one rung, are shown for SSPE cases 1 and 2. A majority of Type I and a minority of Type II tau filaments are each made of two copies of a single protofilament arranged in different ways (ultrastructural polymorphs). Resolutions and filament percentages: SSPE case 1: Type I CTE filament 2.3 Å, 92%; Type II CTE filament 5.1 Å, 8%. SSPE case 2: Type I CTE filament 3.0 Å, 91%; Type II CTE filament 3.5 Å, 9%. Scale bar, 5 nm. b Cryo-EM density maps (grey transparent) of SSPE Type I and Type II tau filaments and the atomic models coloured blue (Type I) and orange (Type II). c SSPE Type I (blue) and Type II (orange) filaments overlaid with CTE Type I (magenta) and CTE Type II (magenta) filaments. The filament core extends from tau residues K274/S305-R379