Pre-aggregation kinetics and intermediates of α-synuclein monitored by the ESIPT probe 7MFE

Area of Science:

• Biochemistry
• Neuroscience
• Materials Science

Background:

• Amyloid diseases are characterized by protein fibril formation with crossed β-sheet structure.
• Oligomeric intermediates are implicated in cellular toxicity but remain poorly defined.
• Understanding amyloid precursor dynamics is crucial for neurodegenerative disease research.

Purpose of the Study:

• To detect and characterize amyloid precursors during protein aggregation.
• To develop a kinetic model for amyloid formation, including novel catalytic factors.
• To investigate the role of excited state intramolecular protein transfer (ESIPT) probes in monitoring aggregation.

Main Methods:

• Utilized novel ESIPT probes (7MFE and 6MFC) to monitor α-synuclein (AS) aggregation.
• Acquired and analyzed 140 spectra to resolve contributions of monomeric, intermediate, and fibrillar species.
• Developed a kinetic scheme to simulate aggregation progress curves and identify key parameters.

Main Results:

• Successfully detected and characterized amyloid precursors using ESIPT probes.
• Resolved discrete molecular species, including monomers, intermediates, and fibrils.
• Identified spontaneous formation of colloidal nanoparticles catalyzing aggregation at ≥37°C.

Conclusions:

• The study provides a detailed kinetic model for amyloid aggregation, incorporating nanoparticle catalysis.
• Novel ESIPT probes offer a sensitive method for characterizing amyloid precursors.
• Findings offer new insights into the mechanisms underlying amyloid diseases and protein misfolding.