In situ kinetic measurements of α-synuclein aggregation reveal large population of short-lived oligomers


Change log
Authors
Zurlo, Enrico 
Kumar, Pravin 
Meisl, Georg 
Dear, Alexander J. 
Mondal, Dipro 
Abstract

Knowledge of the mechanisms of assembly of amyloid proteins into aggregates is of central importance in building an understanding of neurodegenerative disease. Given that oligomeric intermediates formed during the aggregation reaction are believed to be the major toxic species, methods to track such intermediates are clearly needed. Here we present a method, electron paramagnetic resonance (EPR), by which the amount of intermediates can be measured over the course of the aggregation, directly in the reacting solution, without the need for separation. We use this approach to investigate the aggregation of α-synuclein (αS), a synaptic protein implicated in Parkinson’s disease and find a large population of oligomeric species. Our results show that these are primary oligomers, formed directly from monomeric species, rather than oligomers formed by secondary nucleation processes, and that they are short-lived, the majority of them dissociates rather than converts to fibrils. As demonstrated here, EPR offers the means to detect such short-lived intermediate species directly in situ. As it relies only on the change in size of the detected species, it will be applicable to a wide range of self-assembling systems, making accessible the kinetics of intermediates and thus allowing the determination of their rates of formation and conversion, key processes in the self-assembly reaction.

Description

Funder: Lindemann Trust Fellowship, English-Speaking Union

Keywords
Research Article, Physical sciences, Biology and life sciences, Research and analysis methods
Journal Title
PLOS ONE
Conference Name
Journal ISSN
1932-6203
Volume Title
16
Publisher
Public Library of Science
Sponsorship
Foundation for Fundamental Research on Matter (10SMPA04 in the context of the program entitled ‘‘A Single Molecule View on Protein Aggregation)
NWO Dutch Organization for Science (711.014.003)