کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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2186149 | 1096037 | 2010 | 12 صفحه PDF | دانلود رایگان |
α-Synuclein is a major component of filamentous inclusions that are histological hallmarks of Parkinson's disease and other α-synucleinopathies. Previous analyses have revealed that several polyphenols inhibit α-synuclein assembly with low micromolar IC50 values, and that SDS-stable, noncytotoxic soluble α-synuclein oligomers are formed in their presence. Structural elucidation of inhibitor-bound α-synuclein oligomers is obviously required for the better understanding of the inhibitory mechanism. In order to characterize inhibitor-bound α-synucleins in detail, we have prepared α-synuclein dimers in the presence of polyphenol inhibitors, exifone, gossypetin, and dopamine, and purified the products. Peptide mapping and mass spectrometric analysis revealed that exifone-treated α-synuclein monomer and dimer were oxidized at all four methionine residues of α-synuclein. Immunoblot analysis and redox-cycling staining of endoproteinase Asp-N-digested products showed that the N-terminal region (1–60) is involved in the dimerization and exifone binding of α-synuclein. Ultra-high-field NMR analysis of inhibitor-bound α-synuclein dimers showed that the signals derived from the N-terminal region of α-synuclein exhibited line broadening, confirming that the N-terminal region is involved in inhibitor-induced dimerization. The C-terminal portion still predominantly exhibited the random-coil character observed in monomeric α-synuclein. We propose that the N-terminal region of α-synuclein plays a key role in the formation of α-synuclein assemblies.
Journal: Journal of Molecular Biology - Volume 395, Issue 3, 22 January 2010, Pages 445–456