STRUCTURE AND ASSEMBLY OF HELICAL PLANT VIRUSES

螺旋植物病毒的结构和组装

• 批准号: 3282726
• 负责人: GERALD J STUBBS
• 金额: $ 20.44万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1983
• 资助国家: 美国
• 起止时间: 1983-09-01 至 1992-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3282726
• 关键词: RNA virus; X ray crystallography; carboxyl group; electron density; nuclear magnetic resonance spectroscopy; nucleic acid structure; plant virus; protein structure; tobacco mosaic virus; virus assembly; virus morphology; virus protein

Immediate objective of this proposal is to describe the particle of tobacco mosaic virus (TMV) and other helical viruses, including the distantly related TMV strain cucumber green mottle mosaic virus (watermelon strain) and the unrelated tobacco rattle virus (TRV), in molecular detail. This forms part of a broader objective: to study the process of macromolecular assembly; in particular, the assembly of macromolecular structures involving proteins and nucleic acids. The present model of TMV has been refined against data at 2.9A resolution to an R factor of 0.10, using the retrained least squares procedure of Hendrickson and Konnert, adapted for fiber diffraction data. Difference Fourier maps have been used to correct the model and locate water molecules. This refinement will continue, and we will continue to improve the difference Fourier technique, which we have recently adapted to take into consideration the special problems of fiber diffraction. The refined model will be used to further elucidate the mechanism of assembly of TMV. Specimens of TMV at low pH will be set up and diffraction patterns recorded. Electron density maps of TMV at low pH will directly reveal the interactions between carboxyl groups from different subunits. These interactions provide a switch, which is used in the assembly and disassembly of the virus. X-ray fiber diffraction studies of CGMMV-W will continue. We plan to search for heavy-atom derivatives in addition to the recently found lead derivative, and to use these derivatives to begin the process of phase determination and calculation of an electron density map, initially at low resolution. Stocks will be built up of the TMV strain U2, for similar work in the future. We plan to improve the quality of our TRV diffraction patterns, by varying the solution conditions under which specimens for X- ray diffraction experiments are made.

这项提议的直接目标是描述粒子 烟草花叶病毒(TMV)和其他螺旋病毒，包括 黄瓜绿斑驳花叶病毒远缘株系 病毒(西瓜株)和无关的烟草摇铃病毒 (Trv)，分子细节。这构成了更广泛的 前言：目的：研究大分子组装过程。 特别是，涉及到的大分子结构的组装 蛋白质和核酸。 目前的TMV模型已经针对2.9A的数据进行了改进 分辨率为R系数0.10，使用重新训练的最小二乘 适用于纤维的Hendrickson和Konnert手术 衍射数据。差分傅立叶映射已被用于 修正模型并确定水分子的位置。这一改进 将继续，我们将继续改善差异 傅立叶技术，我们最近对其进行了调整 考虑光纤衍射的特殊问题。这个 精炼的模型将被用来进一步阐明 烟草花叶病毒的组装。将建立低pH值下的烟草花叶病毒样本并 记录了衍射图。烟草花叶病毒的电子密度图 低pH值将直接揭示羧基之间的相互作用 来自不同亚基的组。这些交互提供了一种 开关，用于病毒的组装和拆卸。 CGMMV-W的X射线光纤衍射研究将继续进行。我们 除了寻找重原子衍生品外，还计划寻找重原子衍生品 最近发现的铅衍生物，并使用这些衍生品来 开始相位确定和计算过程 电子密度图，最初为低分辨率。股票将会是 建立了烟草花叶病毒U2株系，为今后类似的工作做好准备。 我们计划提高我们的TRV衍射图的质量， 通过改变溶液条件，样品的X- 进行了光线衍射实验。