Pathologicalconditions of neurodegeneration are coincident with aggregation ofexcess α-synuclein, which advances to PD.2 Here, we use a low-temperature (T) system19−21 to introduce fine-tuned, continuously controlled confinement, andlocalization of an electron paramagnetic resonance (EPR) spin probein the α-synuclein protein–solvent regions, to revealfundamental molecular-mechanical and dynamical properties of humanα-synuclein oligomers and fibrils. Here, SNCA is linked to Parkinson disease.