Lipid Dynamics and Phase Transition within α-Synuclein Amyloid Fibrils

The deposition of coassemblies made of the small presynaptic protein, α-synuclein, and lipids in the brains of patients is the hallmark of Parkinson's disease. In this study, we used natural abundance 13 C and 31 P magic-angle spinning nuclear magnetic resonance spectroscopy together with cryo-electron microscopy and differential scanning calorimetry to characterize the fibrils formed by α-synuclein in the presence of vesicles made of 1,2-dimyristoyl- sn -glycero-3-phospho-L-serine or 1,2-dilauroyl- sn -glycero-3-phospho-L-serine. Our results show that these lipids coassemble with α-synuclein molecules to give thin and curly amyloid fibrils. The coassembly leads to slower and more isotropic reorientation of lipid molecular segments and a decrease in both the temperature and enthalpy of the lipid chain-melting compared with those in the protein-free lipid lamellar phase. These findings provide new insights into the properties of lipids within protein-lipid assemblies that can be associated with Parkinson's disease.