Development of a high-pressure treatment for amyloidosis

1.鸡溶菌酶的二硫键缺失变异体自缔合形成一个含有分子间β结构的17-S组合。经过几周到几个月的长时间孵育，淀粉样原纤维自发形成。不涉及特定的、部分展开的构象，纤维从本质上展开的单体状态开始形成，并通过具有自发建立的分子间β-结构的前体形成。17-S前兆在几百到两千巴的静水压力下发生可逆解离。它的吉布斯缔合能为-23.3kJ，每摩尔单体单位体积增加52.7ml，并且在初始缔合步骤中涉及疏水残基的相互作用。通过在变压下进行二维核磁共振测量，发现在1%的种群中出现了正常细胞内PrP^c蛋白的亚稳构象，其中螺旋B是…更多的DC无序。这种亚稳态构象最符合逻辑的是PrP^*，它与PrP^c通过与模板PrP^lt；SC&gt；相互作用而转化为有感染性的普恩蛋白(PrP^lt；SC&gt；)的步骤有关。另一方面，通过氢-氚交换测量和分子动力学模拟，研究了小鼠Pron蛋白的纤维形成片段的构象特征。纤维的形成涉及聚丙氨酸的堆积。在用高压核磁共振波谱测定的蛋白质的残基稳定性和用CPMG方法测定的常压下的缓慢波动之间存在相关性。这表明，高压核磁共振揭示的亚稳构象可以在生理条件下通过缓慢的构象涨落获得。空洞存在于波动较大的部位，这强烈表明，对与空洞结合的分子的筛选有助于开发治疗Pron病或淀粉样变性的药物。较少

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