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首页> 外文期刊>Journal of Molecular Biology >X-RAY DIFFRACTION OF SCRAPIE PRION RODS AND PRP PEPTIDES
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X-RAY DIFFRACTION OF SCRAPIE PRION RODS AND PRP PEPTIDES

机译：蛋白棒和PRP肽的X射线衍射

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Certain neurodegenerative diseases in humans and animals are caused by small proteinaceous infectious particles called prions, Limited proteolysis and detergent extraction of the prions containing PrPSc generate prion rods that are composed of a polypeptide having an apparent molecular mass of 27 to 30 kDa. This polypeptide, termed prion protein PrP 27-30, has a ragged N terminus that begins at about residue 90, but retains scrapie infectivity. Moreover, the findings in a patient having an inherited prion disease of a truncated PrP with its C terminus at residue 145 suggest that the residues 90 to 145 may be of particular importance in the pathogenesis of prion diseases. To determine the three-dimensional organization of prion rods and to identify the core region involved in amyloid formation, we recorded X-ray diffraction patterns from rods purified from scrapie-infected Syrian hamster (SHa) brains which contain PrP 27-30, and from synthetic SHaPrP peptides. Three peptides were studied corresponding to residues 113 to 120 (peptide A8A, an octamer composed of glycines and alanines), 109 to 122 (H1, the first predicted alpha-helical region of PrPC), and 90 to 145 (a 56 residue peptide containing both H1 and the second predicted alpha-helical region of PrPC, H2). Electron microscopy, carried out in parallel with the X-ray measurements, revealed that all the samples formed linear polymers which were similar to 60 to similar to 200 Angstrom wide, with fibrillar or ribbon-like morphology. Gels and dried preparations of prion rods gave X-ray patterns that indicated a beta-sheet conformation, in which the hydrogen bond distance was 4.72 Angstrom and the intersheet distance was 8.82 Angstrom. For the three PrP peptides, the intersheet spacings varied widely, owing to the side-chains of the residues involved in the formation of the beta-sheet interactions, i.e., 5.13 Angstrom for A8A, 5.91 Angstrom for lyophilized H1, 7.99 Angstrom from solubilized and dried H1 and 9.15 Angstrom for the peptide SHa 90-145. The intersheet distance of PrP 27-30 was thus within the observed range for the peptides, and suggests that the amyloidogenic core of PrP is closely modeled by the peptide SHa 90-145. (C) 1995 Academic Press Limited [References: 41]
机译：人和动物中的某些神经退行性疾病是由称为small病毒的小蛋白质感染性颗粒引起的。蛋白质的有限水解和含有PrPSc的病毒的去污剂提取会产生generate病毒棒，rod棒由表观分子量为27至30 kDa的多肽组成。该多肽被称为病毒蛋白PrP 27-30，具有一个参差不齐的N末端，起始于大约90位残基，但保留了瘙痒病的传染性。而且，在具有截短的PrP的遗传病毒疾病的患者中的发现，其C末端在残基145处，表明残基90至145在病毒疾病的发病机理中可能特别重要。为了确定of病毒棒的三维组织，并确定参与淀粉样蛋白形成的核心区域，我们记录了从从含有痒病感染的叙利亚仓鼠（SHa）脑（含有PrP 27-30）和合成SHaPrP肽。研究了三种肽，分别对应于残基113至120（肽A8A，由甘氨酸和丙氨酸组成的八聚体），109至122（H1，PrPC的第一个预测的α螺旋区）和90至145（含56个残基的肽） H1和PrPC的第二个预测α-螺旋区域H2）。与X射线测量平行进行的电子显微镜检查显示，所有样品均形成线型聚合物，其线形或带状形态类似于60到200埃宽。 ion病毒棒的凝胶和干燥制剂产生的X射线图表明β-片层构象，其中氢键距离为4.72埃，片间距离为8.82埃。对于这三种PrP肽，由于参与形成β-折叠相互作用的残基的侧链，层间间距变化很大，即A8A为5.13埃，冻干的H1为5.91埃，溶解的H1为7.99埃，肽SHa 90-145的干燥H1和9.15埃。因此，PrP 27-30的层间距离在该肽的观察范围内，并且表明PrP的淀粉样蛋白形成核心是由肽SHa 90-145紧密建模的。 （C）1995 Academic Press Limited [参考号：41]

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