NMR of alpha-synuclein-polyamine complexes elucidates the mechanism and kinetics of induced aggregation.
The aggregation of alpha-synuclein is characteristic of Parkinson's disease (PD) and other neurodegenerative synucleinopathies. The 140-aa protein is natively unstructured; thus, ligands binding to the monomeric form are of therapeutic interest. Biogenic polyamines promote the aggregation of alpha-synuclein and may constitute endogenous agents modulating the pathogenesis of PD. We characterized the complexes of natural and synthetic polyamines with alpha-synuclein by NMR and assigned the binding site to C-terminal residues 109-140. Dissociation constants were derived from chemical shift perturbations. Greater polyamine charge (+2 --> +5) correlated with increased affinity and enhancement of fibrillation, for which we propose a simple kinetic mechanism involving a dimeric nucleation center. According to the analysis, polyamines increase the extent of nucleation by approximately 10(4) and the rate of monomer addition approximately 40-fold. Significant secondary structure is not induced in monomeric alpha-synuclein by polyamines at 15 degrees C. Instead, NMR reveals changes in a region (aa 22-93) far removed from the polyamine binding site and presumed to adopt the beta-sheet conformation characteristic of fibrillar alpha-synuclein. We conclude that the C-terminal domain acts as a regulator of alpha-synuclein aggregation.
Fernández
Claudio O
CO
LANAIS RMN 300, Laboratorio Nacional de Resonancia Magnética, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina. cfernand@ffyb.uba.ar <cfernand@ffyb.uba.ar>
Hoyer
Wolfgang
W
Zweckstetter
Markus
M
Jares-Erijman
Elizabeth A
EA
Subramaniam
Vinod
V
Griesinger
Christian
C
Jovin
Thomas M
TM
D000595:Amino Acid Sequence; D052160:Benzothiazoles; D001665:Binding Sites; D005456:Fluorescent Dyes / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009419:Nerve Tissue Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D019906:Nuclear Magnetic Resonance, Biomolecular; D010300:Parkinson Disease / Q000378:metabolism; D011073:Polyamines / Q000737:chemistry* / Q000378:metabolism*; D017433:Protein Structure, Secondary; D051843:Synucleins; D013844:Thiazoles / Q000378:metabolism; D051844:alpha-Synuclein
D052160:Benzothiazoles; D005456:Fluorescent Dyes; D009419:Nerve Tissue Proteins; D011073:Polyamines; C497604:SNCA protein, human; D051843:Synucleins; D013844:Thiazoles; D051844:alpha-Synuclein; C009462:thioflavin T