Fig. 3: Amplified αSyn fibrils reveal a common protofilament fold.

a Overlay of the PD-PMCA and the MSA-PMCA αSyn fibril structures onto two opposite subunits of recombinant in vitro aggregated αSyn fibrils with PDB IDs 6SSX (termed “polymorph 2A”) and 6SST (termed “polymorph 2B”)20, respectively. Arrows mark relative shifts between the in vitro αSyn fibrils and the PD/MSA-PMCA αSyn fibrils (displayed in light colors) after superimposing the Cα atoms of the opposite subunits (displayed in dark colors). Below, the superposition of single protofilaments is shown, highlighting changes in the C-terminal structure. b Overlay of the MSA-PMCA αSyn fibril structure determined in the current study (labeled “from MSA”) onto structures determined for αSyn fibrils extracted from the brains of individuals with MSA. The ex vivo MSA fibril structures (PDB IDs 6XYO, 6XYP, and 6XYQ)13 are colored in shades of green, blue, and yellow, respectively, with amino acids from subunit B labeled with an additional prime.