Preparation of α-Synuclein Amyloid Assemblies for Toxicity Experiments

Amyloid assemblies of certain proteins, including the Parkinson disease-related protein α-synuclein, are commonly associated with the development and spreading of neurodegenerative diseases, although the nature of the most toxic forms and the mechanisms by which they trigger neurodegeneration remain largely unknown. This is at least in part due to the inherent challenges involved in the preparation of stable and structurally homogeneous samples of amyloid assemblies that could be used in toxicity experiments. Here, we describe the preparation of two different types of stable α-synuclein amyloid assemblies, namely a kinetically trapped oligomeric species and a propagating-competent fibrillar polymorph. The degree of heterogeneity in the samples has been defined and carefully minimized, thus allowing for meaningful structure-toxicity relationships in different α-synuclein amyloid assemblies to be established.