Figure 16.

Negatively stained EM images of γ-Syn filament pairs and schematics of our models. (a) Smaller filaments. Image on the far left is averaged from 51 pairs and that on the right is an individual filament pair. The yellow rectangles represent models of Υ-Syn octamers stacked end-on. (b) Averaged and an individual image for larger filaments. Red rectangles represent models of hexadecamers stacked end-on. (c). Flattened represention for two subunits of the octamer inner barrel formed by Sy2,3,8. (d) Flattened representation for two subunits of outer 32-stranded β-barrels formed by Sy1,3,5,6 and by the Sy7 β-hairpin connecting Sy6 to Sy8, and four short β-strands of the Ct domain. The last two Ct strands could be from the same octamers as illustrated or from adjacent octamers. These barrels would stack end-on to form the outer walls of the filaments. (e) Wedge representation of a central cross-section of the two concentric β-barrels. The central region would be filled with lipid alkyl chains. The β-barrel parameters of a hexadecamer would be N = 48, S/N = 1.0, D = 9.2 nm, P = 21 nm and N = 64, S/N = 0.75, D = 11.1 nm, P = 19 nm.