Solution structure of Syrian hamster prion protein rPrP(90-231)
Solution structure of Syrian hamster prion protein rPrP(90-231)
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DOI：
10.1021/bi982878x
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发表时间：
1999-04-27
期刊：
影响因子：
2.9
通讯作者：
James, TL
中科院分区：
文献类型：
--
作者：
Liu, H;Farr-Jones, S;James, TL
核磁共振（NMR）已被用于细化叙利亚仓鼠（SHa）朊病毒蛋白rPrP(90 - 231)的结构，该结构与羊瘙痒症朊病毒蛋白PrP^{Sc}的具有感染性的抗蛋白酶核心相对应。rPrP(90 - 231)的结构在光谱学和免疫学上经过重折叠后类似于正常的细胞异构体PrP^{C}，已使用多维NMR进行了研究；初步结果已发表[James等人（1997年）《美国国家科学院院刊》94卷，10086 - 10091页]。我们现在报告更精确的细化结果，揭示了重要的结构和动态特征，这些特征可能与朊病毒疾病相关的生物学观察结果有关。结构细化基于2778个明确指定的核奥弗豪泽效应（NOE）连接性、297个模糊的NOE限制以及63个标量耦合常数（^{3}J_{HNHα}）。该结构由使用ARIA/X - PLOR计算的100个结构中得分最高的25个结构组成的集合来表示，并使用带有明确水分子壳层的AMBER 4.1力场通过受限分子动力学进一步细化。rPrP(90 - 231)结构的特征是具有一个核心结构域（残基125 - 228），其主链原子的均方根偏差（RMSD）为0.67埃，由三个α - 螺旋（残基144 - 154、172 - 193和200 - 227）以及两个短的反平行β - 链（残基129 - 131和161 - 163）组成。N - 末端（残基90 - 119）大部分是无结构的，尽管存在一些稀疏且微弱的中程NOE，暗示存在弯曲或转角。核心结构域和柔性N - 末端之间的过渡区域，即残基113 - 128，由疏水残基或甘氨酸组成，在水溶液中不具有任何规则的二级结构。在这个疏水簇内大约有30个中程和长程NOE，所以它明显具有结构。多个离散的构象是明显的，暗示可能存在一种或多种亚稳态，这可能在PrP^{C}向PrP^{Sc}的转化中起作用。为了更全面地了解rPrP(90 - 231)，已使用酰胺氢 - 氘交换以及N - 15 NMR弛豫时间（T₁和T₂）和N - 15{^{H - 1}}NOE测量来研究其动力学。该结构与先前报道的比较表明，可能存在序列依赖性特征，这可能反映在朊病毒疾病传播的物种屏障中。
NMR has been used to refine the structure of Syrian hamster (SHa) prion protein rPrP(90-231), which is commensurate with the infectious protease-resistant core of the scrapie prion protein PrPSc. The structure of rPrP(90-231), refolded to resemble the normal cellular isoform PrPC spectroscopically and immunologically, has been studied using multidimensional NMR; initial results were published [James et al. (1997) Proc. Natl. Acad. Sci. U.S.A. 94, 10086-10091]. We now report refinement with better definition revealing important structural and dynamic features which can be related to biological observations pertinent to prion diseases. Structure refinement was based on 2778 unambiguously assigned nuclear Overhauser effect (NOE) connectivities, 297 ambiguous NOE restraints, and 63 scalar coupling constants ((3)J(HNHa)). The structure is represented by an ensemble of 25 best-scoring structures from 100 structures calculated using ARIA/X-PLOR and further refined with restrained molecular dynamics using the AMBER 4.1 force field with an explicit shell of water molecules. The rPrP(90-231) structure features a core domain (residues 125-228), with a backbone atomic root-mean-square deviation (RMSD) of 0.67 Angstrom, consisting of three alpha-helices (residues 144-154, 172-193, and 200-227) and two short antiparallel beta-strands (residues 129-131 and 161-163). The N-terminus (residues 90-119) is largely unstructured despite some sparse and weak medium-range NOEs implying the existence of bends or turns. The transition region between the core domain and flexible N-terminus, i.e., residues 113-128, consists of hydrophobic residues or glycines and does not adopt any regular secondary structure in aqueous solution. There are about 30 medium- and long-range NOEs within this hydrophobic cluster, so it clearly manifests structure. Multiple discrete conformations are evident, implying the possible existence of one or more metastable states, which may feature in conversion of PrPC to PrPSc. To obtain a more comprehensive picture of rPrP(90-231), dynamics have been studied using amide hydrogen-deuterium exchange and N-15 NMR relaxation times (T-1 and T-2) and N-15{H-1} NOE measurements. Comparison of the structure with previous reports suggests sequence-dependent features that may be reflected in a species barrier to prion disease transmission.