FIGURE 1.

Structural and binding properties of the tau protein. (A) Side view of [¹⁸F]PM-PBB3 binding to straight filaments in AD. (B) Images from cryo-EM showing paired helical filaments and straight filaments in AD with bound [¹⁸F]PM-PBB3 (+APN-1607) and without [¹⁸F]PM-PBB3 (–APN-1607). Reproduced from Shi et al. (2021b) with permission from Springer Nature. (C) Chemical structure of a tau protofibril, representing the four high-affinity binding sites for tau tracers. S1, S3, and S4 show the core sites, and S2 shows the surface site. Reproduced from Murugan et al. (2018) with permission from American Chemical Society.