Analysis of assembly mechanism of spherical virus based on its high resolution three-dimensional structure

基于高分辨率三维结构的球形病毒组装机制分析

• 批准号: 10680634
• 负责人: FUKUYAMA Keiichi
• 金额: $ 2.24万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10680634/
• 关键词: tobacco necrosis virus; x-ray crystallographic analysis; three dimensioual structure of virus; protein-protein interactiou; assembly mechauism; ウイルスの立体構造

Tobacco necrosis virus (TNV) is a spherical virus that contains ss-RNA (1.3x10ィイD16ィエD1 Da) as a genome. TNV causes such plants as C. quinoa and tulip necrotic lesions. TNV coat protein has 276 amino acid residues; the amino acid sequence was determined by a combination of peptide and DNA sequencing. 180 copies of the protein assemble to form T=3 icosahedral shell. Thus, the virus shell has three stereochemically independent subunits (A, B and C) with identical primary structure.TNV crystallized in space group P4ィイD22ィエD232, with a=336.4Å. Unit cell contains two TNV particles. Diffraction data of TNV crystals were collected to 2.25Å resolution using synchotron radiation and Weissenberg camera for macromolecules at BL6A, Photon Factory, Tsukuba. The structure was solved by averaging the electron density of non-crystallographic units and refined by XPLOR to R=25.3%.The subunits have a fold of jelly roll β-barrel. Respective N-terminal 86, 87 and 56 residues of A,B and C subunits are disordered. The segment ordered only in C subunit (arm) produces diversity of the subunit interactions; A subunits form pentermers at five-fold axis, whereas B and C subunits form hexamers at icosahedral three-fold axis, where three arms of C-subunits form a β-annulus. Five calcium ion per icosahedral asymmetric unit were identified. These are located at the subunit interfaces.

烟草坏死病毒（TNV）是一种球形病毒，含有ss-RNA（1.3 × 10 - 6 kDa D16 kDa D1）作为基因组。TNV引起C.藜麦和郁金香坏死病变。TNV外壳蛋白具有276个氨基酸残基;通过肽和DNA测序的组合确定氨基酸序列。180个拷贝的蛋白质组装形成T=3的二十面体壳。因此，病毒外壳具有三个立体化学独立的亚基（A、B和C），具有相同的一级结构。单位细胞含有两个TNV颗粒。TNV晶体的衍射数据在BL 6A，Photon Factory，Tsukuba使用同步辐射和用于大分子的Weissenberg照相机收集到2.25 μ m分辨率。通过对非晶体学单元的电子密度进行平均，得到了晶体结构，并通过XPLOR修正到R= 25.3%，亚基具有一个果冻卷β-桶的折叠。A、B和C亚基各自的N-末端86、87和56个残基是无序的。仅在C亚基（臂）中有序的片段产生亚基相互作用的多样性; A亚基在五重轴处形成五聚体，而B和C亚基在二十面体三重轴处形成六聚体，其中C亚基的三个臂形成β环。每个二十面体不对称单元中有5个钙离子。它们位于子单元接口处。