title: Stabilization of partially folded conformation during alpha-synuclein oligomerization in both purified and cytosolic preparations.
abstract: Aggregation of alpha-synuclein is tightly associated with many neurodegenerative diseases, such as Parkinson's disease, dementia with Lewy body, Lewy body variant of Alzheimer's disease, multiple system atrophy, and Hallervorden-Spatz disease, implicating a crucial role of aggregated forms of alpha-synuclein in the pathogenesis. Here, we examined the effect of elevated temperature on the oligomerization and structural changes of alpha-synuclein in the early stage of aggregation and show that self-assembly is crucial for the stabilization of a partially folded conformation. The efficiency of alpha-synuclein oligomerization increased proportional to the temperature increase, both in purified form and in crude cytosolic preparation. This oligomerization coincided with a small but reproducible change in the circular dichroism spectrum and an increase in the 1-anilinonaphthalene-8-sulfonic acid binding. The hydrodynamic dimensions of the dimer measured by size exclusion chromatography suggest a pre-molten globule-like structure. These data suggest that partially folded alpha-synuclein, which is unstable in the monomeric form, is stabilized by self-assembly and that these oligomers may evolve into the fibril nucleus.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, USA.
authors.forename: V N
authors.initials: VN
authors.lastname: Uversky
authors.forename: H J
authors.initials: HJ
authors.lastname: Lee
authors.forename: J
authors.initials: J
authors.lastname: Li
authors.forename: A L
authors.initials: AL
authors.lastname: Fink
authors.forename: S J
authors.initials: SJ
authors.lastname: Lee
mesh_terms: D000818:Animals; D001704:Biopolymers / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D019556:COS Cells; D002942:Circular Dichroism; D005453:Fluorescence; D007700:Kinetics; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017510:Protein Folding; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013056:Spectrophotometry, Ultraviolet; D051843:Synucleins; D013696:Temperature; D051844:alpha-Synuclein
chemical_list: D001704:Biopolymers; D009419:Nerve Tissue Proteins; D011994:Recombinant Proteins; D051843:Synucleins; D051844:alpha-Synuclein