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Alpha Synuclein only Forms Fibrils In Vitro when Larger than its Critical Size of 70 Monomers.

Accepted version
Peer-reviewed

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Type

Article

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Authors

Sanchez, Santiago Enrique 
Whiten, Daniel R 
Ruggeri, Francesco Simone 
Hidari, Eric 

Abstract

The aggregation of α-synuclein into small soluble aggregates and then fibrils is important in the development and spreading of aggregates through the brain in Parkinson's disease. Fibrillar aggregates can grow by monomer addition and then break into fragments that could spread into neighboring cells. The rate constants for fibril elongation and fragmentation have been measured but it is not known how large an aggregate needs to be before fibril formation is thermodynamically favorable. This critical size is an important parameter controlling at what stage in an aggregation reaction fibrils can form and replicate. We determined this value to be approximately 70 monomers using super-resolution and atomic force microscopy imaging of individual α-synuclein aggregates formed in solution over long time periods. This represents the minimum size for a stable α-synuclein fibril and we hypothesis the formation of aggregates of this size in a cell represents a tipping point at which rapid replication occurs.

Description

Keywords

fibrils, protein aggregation, single molecule AFM, single molecule fluorescence, α-synuclein, Amyloid, Brain, Humans, Microscopy, Atomic Force, Parkinson Disease, Particle Size, Protein Aggregates, Thermodynamics, alpha-Synuclein

Journal Title

Chembiochem

Conference Name

Journal ISSN

1439-4227
1439-7633

Volume Title

22

Publisher

Wiley

Rights

All rights reserved
Sponsorship
European Research Council (669237)
Royal Society (RP150066)
The authors wish to thank Swapan Preet for expression and purification of α-synuclein. This work was supported by the UK Dementia Research Institute which receives its funding from DRI Ltd., funded by the UK Medical Research Council, Alzheimer’s Society and Alzheimer’s Research UK, and by the European Research Council Grant Number 669237 and the Royal Society. DRW was supported by a Herchel Smith Postdoctoral Research Fellowship.