Development of a high-pressure treatment for amyloidosis

1.一种缺乏二硫键的鸡溶菌酶变体自缔合成含有分子间β-结构的17-S组合。经过数周至数月的长时间孵育，淀粉样原纤维自发形成。不涉及特定的部分未折叠构象异构体，并且原纤维从固有未折叠的单体状态开始并通过具有分子间β-结构的自发建立的前体形成。17-S前体在几百到两千巴的静水压力下可逆地解离。其特征在于缔合的吉布斯自由能为-23.3 kJ，体积增加为52.7 ml/mol单体单元，并且在初始缔合步骤中涉及疏水残基的相互作用。通过在可变压力下进行二维NMR测量，发现朊病毒蛋白（PrP^c）的正常细胞亚型的亚稳构象存在于1%的群体中，其中螺旋B和 ...更多信息 d C是无序的。这种亚稳态构象体最符合逻辑地是PrP^*，它参与了PrP^c通过与模板PrP^相互作用转化为感染性朊病毒蛋白（PrP^）的步骤<Sc><Sc>。另一方面，已通过使用氢-氘交换测量和分子动力学模拟的小鼠朊病毒蛋白的原纤维形成片段的构象特征进行了研究。原纤维的形成被证明涉及聚丙氨酸堆积。存在一个相关性朊病毒蛋白之间的残留物的稳定性确定的高压NMR光谱和缓慢波动的CPMG方法在环境压力下。这表明高压NMR所揭示的亚稳态构象可以通过生理条件下的缓慢构象波动来获得。在波动较大的部位存在空腔，这强烈表明筛选与空腔结合的分子导致开发用于治疗朊病毒疾病或淀粉样变性的药物。少

1. A disulfide-deficient variant of hen lysozyme self-associates into a 17-S assemblage that contains intermolecular beta-structure. Upon prolonged incubation over weeks to months, amyloid-like fibrils are spontaneously formed. No specific, partially unfolded conformer is involved, and fibrils are formed starting from an intrinsically unfolded monomeric state and passing through a precursor with a spontaneous build-up of intermolecular beta-structure.2. The 17-S precursor reversibly dissociates under hydrostatic pressure of several hundred to two thousand bars. It is characterized with a Gibbs energy for association of -23.3 kJ and a volume increase of 52.7 ml per mol of monomer unit, and involves interaction of hydrophobic residues in the initial association step.3. By carrying out two-dimensional NMR measurements under variable pressure, a metastable conformer of the normal cellular isoform of prion protein (PrP^c) has been found to occur at a population of 1 %, in which helices B an … More d C are disordered. This metastable conformer is most logically PrP^* that is implicated in the step for transformation of PrP^c to the infectious prion protein (PrP^<Sc>) via interaction with a template PrP^<Sc>. On the other hand, the conformational characteristics of a fibril-forming fragment of the mouse prion protein have been investigated by using hydrogen-deuterium exchange measurements and molecular dynamics simulations. Fibril formation was shown to involve polyalanine stacking.4. There exists a correlation for prion protein between the residue-wise stability determined by high-pressure NMR spectroscopy and slow fluctuations determined by the CPMG method at ambient pressure. This indicates that the metastable conformer revealed by high-pressure NMR can be acquired through slow conformational fluctuations under physiological conditions. Cavities exist at the site of large fluctuation, which strongly suggests that the screening for the molecules that bind to the cavity leads to the development of drugs for the treatment of prion disease or amyloidosis. Less