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Single-molecule FRET studies on alpha-synuclein oligomerization of Parkinson's disease genetically related mutants.


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Authors

Tosatto, Laura 
Horrocks, Mathew H 
Dear, Alexander J 
Knowles, Tuomas PJ 
Dalla Serra, Mauro 

Abstract

Oligomers of alpha-synuclein are toxic to cells and have been proposed to play a key role in the etiopathogenesis of Parkinson's disease. As certain missense mutations in the gene encoding for alpha-synuclein induce early-onset forms of the disease, it has been suggested that these variants might have an inherent tendency to produce high concentrations of oligomers during aggregation, although a direct experimental evidence for this is still missing. We used single-molecule Förster Resonance Energy Transfer to visualize directly the protein self-assembly process by wild-type alpha-synuclein and A53T, A30P and E46K mutants and to compare the structural properties of the ensemble of oligomers generated. We found that the kinetics of oligomer formation correlates with the natural tendency of each variant to acquire beta-sheet structure. Moreover, A53T and A30P showed significant differences in the averaged FRET efficiency of one of the two types of oligomers formed compared to the wild-type oligomers, indicating possible structural variety among the ensemble of species generated. Importantly, we found similar concentrations of oligomers during the lag-phase of the aggregation of wild-type and mutated alpha-synuclein, suggesting that the properties of the ensemble of oligomers generated during self-assembly might be more relevant than their absolute concentration for triggering neurodegeneration.

Description

Keywords

Amino Acid Sequence, Benzothiazoles, Biological Assay, Fluorescence Resonance Energy Transfer, Humans, Kinetics, Molecular Sequence Data, Mutant Proteins, Mutation, Missense, Parkinson Disease, Protein Multimerization, Thiazoles, alpha-Synuclein

Journal Title

Sci Rep

Conference Name

Journal ISSN

2045-2322
2045-2322

Volume Title

5

Publisher

Springer Science and Business Media LLC
Sponsorship
LT has been recipient of a grant PAT Post Doc Outgoing 2009 – 7th Framework Program Marie Curie COFUND actions. NC was funded by a Royal Society Dorothy Hodgkin Research Fellowship and is currently a Ramón y Cajal Research Fellow (Spanish Ministry of Economy and Competitiveness). MHH thanks the Royal Society of Chemistry (Analytical Chemistry Trust Fund) for his studentship. AJD is funded by the Schiff Foundation.