Dopamine cannot promote oligomerization of unoxidized α-synuclein

α-Synuclein is the major component of the filamentous Lewy bodies and Lewy neurites that define neuropathological features of Parkinson’s disease and dementia with Lewy bodies. To investigate the oligomerization process of α-synuclein in association with dopamine (DA), the structural propensities to form oligomers were studied using NMR and other biophysical techniques. The1H-15N HSQC spectra indicated that both N- and C-termini interacted with DA. Although interactions with DA were also observed in the presence of glutathione by ESI-MS, the significant suppression of oligomerization was observed in the size exclusion chromatography, suggesting that oxidations of α-synuclein are required for its oligomerization.