Figure 10. Type 2P model of an α-Syn tetramer with (a) Sy2 and Sy4 forming the core 8-stranded parallel β-barrel, (b) Sy1,3,5, & 8 forming the second 16-stranded parallel β-barrel, and (c) Sy7 + the Ct domain possibly forming an outer 24-stranded antiparallel β-barrel. Residues of the flattened representations are colored as in previous figures. (d) Wedge representation of a central cross-section showing proposed relative positions of β-strands. The Ct segments of the wedge representation are numbered in white and italicized. (e) A central cross-section illustrating degree of conservation of residues. The sequences of the inner two barrels are almost identical for the α-Syn and β-syn families and where they differ on the exterior of Sy3 and Sy5 of the middle barrel they are the same in the β-syn and Υ-Syn families. (f & g) Models of one subunit of the middle and outer β-barrels for β-Syn and positions where residues differ from α-Syn.
Excluding the tentative outer barrel of the 2P model, all trimer and tetramer models described above have diameters consistent with the bead images in Fig. 4.