Elucidation and control of the molecular mechanism of amyloid fibril formation Applications for nano materials

本研究的目的是：(1)通过对β -淀粉样蛋白和β -微球蛋白（β2-m）淀粉样蛋白的研究，建立淀粉样蛋白纤维形成和解离的一般分子模型；(2)阐明各种生物分子或化合物对每种淀粉样变性的共同发病机制的作用，并提出治疗策略；(3)发明淀粉样蛋白纤维形成和解离的控制方法，并将其应用于纳米技术。结果：(1)6个肽对应于β2-m天然结构中7个β片中的6个，并检测了它们的淀粉样变性。在所检测的肽中，肽（21-31）显示纤维形成。(2)在β2-m淀粉样原纤维形成过程中，β2-m的部分展开被认为是其组装成a - β 2m淀粉样原纤维的先决条件。在本研究中，发现低浓度的三氟乙醇和十二烷基硫酸钠可诱导β2-m淀粉样蛋白部分展开，并导致a - β 2m淀粉样蛋白原纤维在中性ph下延伸。(3)多酚或维生素a相关化合物可抑制β-淀粉样蛋白原纤维的原纤维形成，并使体外预形成的原纤维不稳定。(4)建立了等温滴定量热法对淀粉样纤维形成的直接热力学分析。这项研究使我们能够测量热容和焓，并估计淀粉样蛋白在纤维形成过程中构象变化的稳定性和结构信息。本研究的结论是，在阐明体外纤维形成的分子机制方面取得了显著进展。此外，还发现了淀粉样纤维形成和解离的有用特性，可用于纳米技术的应用。

The aims of this study are (1) establishment of general molecular model of amyloid fibril formation and dissociation via the study of beta-amyloid and beta2-microglobulin (β2-m) amyloid (2) elucidation of the effect of various biological molecules or chemical compounds on the common pathogenesis of each amyloidosis, and suggest a strategy for treatment (3) invention of the control method for the formation and dissociation of amyloid fibril, and their application to nanotechnology. Results : (1) six peptides correspond to six of the seven beta sheet in the native structure of β2-m, and examined their amyloidogenisity. Among the peptides examined, peptide(21-31) showed fibril formation. (2) in β2-m amyloid fibril formation, partial unfolding of β2-m is believed to be prerequisite to its assembly into Aβ2M amyloid fibrils. In this study, low concentrations of trifluoroethanol and sodium dodecyl sulfate was found to induce the amyloidogenic partial unfolding of β2-m and result in the extension of Aβ2M amyloid fibrils at a neutral pH. (3) Polyphenols or vitamin A related compounds are found to inhibit the fibril formation of β-amyloid fibrils and to destabilize the preformed fibrils in vitro. (4) a direct thermodynamic analysis of amyloid fibril formation using isothermal titration calorimetry was develpoed. This investigation enables us to measure the heat capacity and enthalpy, and to estimate the stability and structural information on the conformational change of amyloidogenic proteins during fibril formation. As the conclusion of this study, remarkable advance on the clarification of the molecular mechanism of fibril formation in vitro was obtained. Furthermore, useful characteristics of amyloid fibril formation and dissociation for the application to nanotechnology were discovered.