NMR spectra supporting "The release of toxic oligomers from α-synuclein fibrils induces neuronal dysfunction". To probe the structural properties of aS oligomers and fibrils, we used solid-state nuclear magnetic resonance (ssNMR) spectroscopy. Correlations between carbon atoms of residues located in rigid regions of the oligomers/fibrils were detected using 13C–13C dipolar-assisted rotational resonance (DARR) correlation spectra, measured using magic angle spinning (MAS).

Data collection methods: Paramagnetic relaxation enhancement (PRE) measurements. PRE data were acquired using ssNMR employing DARR experiments to probe the membrane interactions of the rigid regions of the αS oligomers and fibrils.

PRE between the oligomers/fibrils and the surfaces of the membranes were measured by incorporating into the lipid membrane 2% of 1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine-N-DTPA gadolinium salt, which carries an unpaired electron on the hydrophilic head group, in the mixture of 5:3:2 of DOPE:DOPS:DOPC (Avanti Polar Lipids Inc., Alabaster, AL, USA) prepared in chloroform solutions.These small quantities of lipid molecules labeled with a paramagnetic centre (PC) induces relaxation in the nucleus of nearby atoms.

PRE experiments probing the insertion of the oligomers/fibrils into the interior of the membrane were carried out using as a paramagnetic lipid with an unpaired electron located at the carbon 16 of the lipid tail (1-palmitoyl-2-stearoyl-[16-doxyl]-sn-glycero-3- phosphocholine).