Lipid Dynamics and Phase Transition within α-Synuclein Amyloid Fibrils

Area of Science:

• Neuroscience
• Biochemistry
• Structural Biology

Background:

• Parkinson's disease (PD) is characterized by protein-lipid coassemblies in the brain.
• Alpha-synuclein (α-synuclein) is a key protein implicated in PD pathogenesis.
• Understanding the structure and properties of these coassemblies is crucial for PD research.

Purpose of the Study:

• To characterize the amyloid fibrils formed by α-synuclein coassembled with specific lipids.
• To investigate the impact of α-synuclein coassembly on lipid properties.
• To gain insights into the molecular basis of protein-lipid interactions in PD.

Main Methods:

• Natural abundance ¹³C and ³¹P magic-angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy.
• Cryo-electron microscopy (cryo-EM).
• Differential scanning calorimetry (DSC).

Main Results:

• α-synuclein and lipids (1,2-dimyristoyl-sn-glycero-3-phospho-L-serine or 1,2-dilauroyl-sn-glycero-3-phospho-L-serine) coassemble into thin, curly amyloid fibrils.
• Lipid molecular segments exhibit slower and more isotropic reorientation within the fibrils.
• Lipid chain-melting temperature and enthalpy decrease compared to protein-free lipid phases.

Conclusions:

• Lipid-protein coassembly significantly alters lipid dynamics and phase behavior.
• These findings provide novel insights into the structural and dynamic properties of lipids within pathological assemblies relevant to Parkinson's disease.
• The study highlights the importance of considering lipid properties in the context of α-synuclein aggregation and PD.