Figure 11. Models of an α-Syn Type 2P octamer with a small central pore. (a-d) Flattened representations for two α-Syn subunits of the four putative β-barrels superimposed on cylinder representations of each barrel. Sy6, Sy7, and Ct1 segments are not part of the core barrels and models of these segments are more speculative; they may be relatively disordered and are not integral components of the model. (e-h) Ribbon representation of an atomic-scale model colored by the rainbow beginning with red and ending with purple. (e) Top view down the axis of the pore. Sy6 and Sy7 segments that connect Sy5 to Sy8 are cyan and the Ct1 segment that connects Sy8 of the inner barrel to Ct2 of the outer barrel is blue-purple. (f) Clipped view of the four concentric β-barrels. (g) Side view down the 2-fold axis of symmetry between the red Sy1 strands. Portions of the outer barrel have been clipped away. (h) Side view rotated by 45⁰ relative to (g) viewed down the axis of 2-fold symmetry formed between the purple Ct6 and green Sy5 strands. (I-m) Cross-sections illustrating side-chain (colored by element) packing between the barrels: (i) Top view, (j) one layer down, (k) two layers down, (l) central layer, (m) side-view showing the positions of the layers. (n-q) Illustration of the surface of conserved core (purple) formed by residues that are identical in α-Syn and β-Syn. The orange tubes are the back-bone trace of residues that are not identical in the two sequences and for which the surfaces are not shown. (n) Top view; one of the Sy7 segments that is deleted in β-Syn is encircled in red. (o) Cross-section of the top segments connecting strands of the β-barrels. The conserved purple portions are at the ends of Sy5 and Sy6. The rest of the connectors are not conserved. (p) Cross-section of the mid-region illustrating dense packing of the conserved core (purple). (q) Side view with the same orientation as in (g).