Direct observation of the interconversion of normal and toxic forms of α-synuclein.
Here, we use single-molecule techniques to study the aggregation of α-synuclein, the protein whose misfolding and deposition is associated with Parkinson's disease. We identify a conformational change from the initially formed oligomers to stable, more compact proteinase-K-resistant oligomers as the key step that leads ultimately to fibril formation. The oligomers formed as a result of the structural conversion generate much higher levels of oxidative stress in rat primary neurons than do the oligomers formed initially, showing that they are more damaging to cells. The structural conversion is remarkably slow, indicating a high kinetic barrier for the conversion and suggesting that there is a significant period of time for the cellular protective machinery to operate and potentially for therapeutic intervention, prior to the onset of cellular damage. In the absence of added soluble protein, the assembly process is reversed and fibrils disaggregate to form stable oligomers, hence acting as a source of cytotoxic species.
Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK.
Nunilo
N
Cremades
Samuel I A
SI
Cohen
Emma
E
Deas
Andrey Y
AY
Abramov
Allen Y
AY
Chen
Angel
A
Orte
Massimo
M
Sandal
Richard W
RW
Clarke
Paul
P
Dunne
Francesco A
FA
Aprile
Carlos W
CW
Bertoncini
Nicholas W
NW
Wood
Tuomas P J
TP
Knowles
Christopher M
CM
Dobson
David
D
Klenerman
D000818:Animals; D002478:Cells, Cultured; D019286:Endopeptidase K / Q000378:metabolism; D031541:Fluorescence Resonance Energy Transfer; D006801:Humans; D007700:Kinetics; D008958:Models, Molecular; D009474:Neurons / Q000378:metabolism; D018384:Oxidative Stress; D051381:Rats; D051844:alpha-Synuclein / Q000737:chemistry* / Q000378:metabolism*
D051844:alpha-Synuclein; D019286:Endopeptidase K