| 研究実績の概要 |
Although the structural stability of globular proteins has been extensively examined, the conformational stability of disease-induced amyloid fibrils is largely unknown. Thus, I performed in-depth studies on the conformational stability of amyloid fibrils at a wide range of temperature. I examined cold and heat denaturation of amyloid fibrils of intrinsically disordered alpha-synuclein (aSN) prepared at various temperatures (298, 310, 323, 333, and 343 K). Formation of typical amyloid fibrils was confirmed by ThT assay, far-UV CD spectra, and AFM images at all temperatures. Despite differences in temperature for aSN amyloidogenesis, all fibrils showed similar core regions with distinct fibril height (i.e., width). As temperature increased from 298 to 383 K, all types of aSN fibrils heat-denatured to monomers from approximately 343 K. Decreasing temperature from 298 to 273 K caused cold denaturation of fibrils to monomers. Intriguingly, the stability of aSN fibrils depended on temperature of preparation of aSN fibrils. aSN fibrils generated at higher temperature showed higher stability at high and low temperature than fibrils formed at lower temperature. aSN fibrils prepared at higher temperature were more resistant against chemical stress than fibrils formed at lower temperature. As temperature where aSN fibrils grow increased, fibrils also showed slower cold, heat, and chemical denaturation. Taken together, the stability of aSN amyloid fibrils depended on growing temperature of fibrils which produced differences in higher order structures of amyloid fibrils.
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