RICE DWARF VIRUS STRUCTURAL STUDIES

水稻矮缩病毒结构研究

• 批准号: 6120887
• 负责人: GUANG Y LU
• 金额: $ 0.9万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-12-01 至 1999-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6120887
• 关键词: biomedical resource; immunology; infection; inflammation; intestines; proteins; virus

Bluetongue virus (BTV) (Reoviridae family, Orbivirus genus) is a non-enveloped, icosahedral double-stranded RNA virus. Several protein layers enclose the genome. Upon cell entry the outer layer is stripped away leaving a core whose surface is composed of VP7. The structure of the trimeric VP7 molecule has been determined using X-ray crystallography. The articulated VP7 subunit consists of two domains, one largely alpha-helical and the other a smaller domain with the familiar 'jelly-roll' topology. The relative orientations of these two domains vary in different crystal forms. A 23 resolution map of the core determined, using electron cryo microscopy (cryoEM) data, reveals 260 trimers of VP7 organized on a rather precise T=13 laevo icosahedral lattice. The VP7 layer occupies a shell between 260
and 345
from the center of the core. Below this radius (230-260
) lies the T=1 layer of 120 molecules of VP3. By fitting the X-ray structure of the individual VP7 trimer to the cryoEM structure, we have generated an atomic model of the VP7 layer of BTV and demonstrated that one of the molecular structures seen in crystals of the isolated VP7 corresponds to the conformation of the molecule in the core. The beta barrel domains of VP7 are external to the core and interact with the protein in the outer layer of the mature virion. The lower alpha-helical domains of VP7 interact with the inner layer of VP3. Adjacent VP7 trimers in the T=13 layer interact principally through well defined regions in the broader lower domains and conform well to the structure expected from the theory of quasi-equivalence, with no significant conformational changes within the individual trimers. The VP3 layer determines the particle size and forms a rather smooth substrate upon which the two dimensional lattice of VP7 trimers is laid down.

蓝舌病毒（BTV）（呼肠孤病毒科，环状病毒属）是一种 无包膜、二十面体双链RNA病毒。 几种蛋白质 层包围着基因组。 进入细胞后，外层是 剥离后留下表面由VP7组成的核心。 这 使用 X 射线确定了三聚体 VP7 分子的结构 晶体学。 铰接的 VP7 亚基由两个结构域组成， 一个主要是α螺旋，另一个是较小的域 熟悉的“果冻卷”拓扑。 这些的相对方向 两个域的晶型不同。 23 分辨率地图 使用冷冻电子显微镜 (cryoEM) 数据确定核心， 揭示了在相当精确的 T=13 laevo 上组织的 VP7 的 260 个三聚体 二十面体晶格。 VP7层占据260和260之间的壳 距离核心中心345。 在此半径 (230-260) 下方 T=1层120个VP3分子。 通过拟合X射线结构 单个 VP7 三聚体到冷冻电镜结构，我们有 生成了 BTV VP7 层的原子模型并演示了 在分离的晶体中看到的分子结构之一 VP7对应于核心分子的构象。 这 VP7 的 β 桶结构域位于核心外部并与 成熟病毒粒子外层的蛋白质。 较低的 VP7 的 α 螺旋结构域与 VP3 的内层相互作用。 T=13 层中相邻的 VP7 三聚体主要通过 更广泛的低域中明确定义的区域并且很好地符合 准等价理论所期望的结构，没有 单个三聚体内的显着构象变化。 这 VP3层决定颗粒大小并形成相当光滑的层 VP7 三聚体的二维晶格所在的基底 放下。