Figure 1 Amyloid filaments of the Sup35 protein prion domain (courtesy of Dr Frank Shewmaker, NIH). Amyloid is a filamentous protein polymer, with strands perpendicular to the long axis of the filament, relative protease-resistance of the protein and special dye staining properties.
Figure 2 Architecture of yeast prion amyloid filaments is an in-register parallel β-sheet. The side chains of each residue form a row along the long axis of the filaments, and interactions among these identical side chains, such as the β-zipper of glutamine or asparagine side chains, enforce the in-register structure. The same interactions explain how conformational information is propagated from the filament to new molecules joining the ends.
Figure 3 Amyloid prions replicate by elongation of amyloid filaments and scission of filaments by the action of chaperones to produce new filaments.
Figure 4 Genetic criteria for identification of prions.
Figure 5 Amyloid filaments in cells of S. cerevisiae infected with the [URE3] prion.
(From Speransky, V. et al. (2001). Prion filament networks in [URE3] cells if Saccaromyces cerevisiae. J. Cell Biol., 153, 1327-1335; with permission.)