Dynamical behavior of human -synuclein studied by quasielastic neutron scattering

藤原 悟; 荒木 克哉*; 松尾 龍人; 八木 寿梓*; 山田 武*; 柴田 薫; 望月 秀樹*

PLOS ONE (Internet), 11(4), p.e0151447_1 - e0151447_17, 2016/04

https://doi.org/10.1371/journal.pone.0151447

Filamentous aggregates (amyloid fibrils) of the protein -synuclein (-Syn) are related to the pathogenesis of Parkinson's disease. To understand the pathogenesis mechanism of this disease, the mechanism of the amyloid fibril formation of -Syn must be elucidated. As a first step toward this ultimate goal, dynamical behavior of -Syn in the monomeric and the fibril states was investigated using quasielastic neutron scattering (QENS). Analysis of the QENS spectra of solution samples of -Syn shows that diffusive global motions are observed in the monomeric state but largely suppressed in the fibril state. However, the amplitude of the side chain motion is shown to be larger in the fibril state than in the monomeric state. This implies that significant solvent space exists within the fibrils, which is attributed to the -Syn molecules within the fibrils having a distribution of conformations. The larger amplitude of the side chain motion in the fibril state than in the monomeric state implies that the fibril state is entropically favorable.

高速炉の冷却系に関する総合試験計画; 炉容器および1次冷却系モデルの検討

上出 英樹; 林 謙二; 軍司 稔; 林田 均; 西村 元彦; 飯塚 透; 木村 暢之; 田中 正暁; 仲井 悟; 望月 弘保; et al.

PNC TN9410 96-279, 51 Pages, 1996/08

PNC-TN9410-96-279.pdf:2.92MB

動力炉・核燃料開発事業団では「原子炉冷却系総合試験」として,高速炉の実用化を目指し,実証炉段階で採用される原子炉冷却系に係る新概念技術の確立を目的とし,原子炉容器から蒸気発生器までの1次,2次冷却系,水蒸気系,崩壊熱除去系を総合的に模擬した大型ナトリウム試験を計画している。実証炉の特徴であるトップエントリー配管システム,炉内冷却器を用い自然循環を積極的に活用した崩壊熱除去系,低温流体循環方式の炉容器壁保護系,一体貫流型蒸気発生器,再循環系を用いた崩壊熱除去運転などを含め配管短縮化,機器のコンパクト化,高信頼性崩壊熱除去システムなどについて熱流動上の課題,構造上の課題を設定し,それらを解決できる試験装置として特に原子炉容器ならびに1次冷却系の試験モデルの検討を行った。特に(1)実証炉の熱流動と構造上の課題に対する解決方策としての充足,(2)熱流動上の課題と構造上の課題のバランス,(3)総合試験として系統全体での複合現象,構成機器間の熱流動的および構造的相互作用の模擬を重視して,試験モデル候補概念の創出,予測解析を含む定量的な比較評価,モデルの選定を行った。さらに,選定モデル候補概念を元に,「原子炉冷却系総合試験」全体の試験装置概念を構築した。

Quasielastic neutron scattering study of human -synuclein; Implication for propensity for amyloid fibril formation

藤原 悟; 荒木 克哉*; 松尾 龍人; 八木 寿梓*; 山田 武*; 柴田 薫; 望月 秀樹*

no journal, , 

A protein -synuclein (-Syn) forms amyloid fibrils. This abnormal protein aggregation is related to pathogenesis of a neuro-degenerative disorder, Parkinson's disease. Propensity for amyloid fibril formation depends on environmental conditions such as pH. We carried out quasielastic neutron scattering experiments to investigate the "dynamic" behavior of -Syn to investigate the relationship between the dynamics and propensity for amyloid fibril formation. The measurements on the solution samples of -Syn in different pH were carried out using a high energy resolution near-backscattering spectrometer, BL02 (DNA), at MLF/J-PARC, Japan. Differences in flexibility of the protein were detected between the different conditions. Since the difference in flexibility is likely to arise from different distributions of conformational substates of -Syn, the results obtained suggest an entropy-driven mechanism of the amyloid fibril formation.