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X-Ray Crystal Structural Analysis of Tobacco Necrosis Virus at 5A Resolution

5A 分辨率下烟草坏死病毒的 X 射线晶体结构分析

基本信息

批准号：
01580053
负责人：
TSUKIHARA Tomitake
金额：
$ 1.54万
依托单位：
Tottori University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1990
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01580053/
关键词：
Tobacco Necrosis Virus Spherical Virus X-Ray Analysis Crystal Structure Molecular Replacement Averaying ウイルス X線回折立体構造

项目摘要

Tobacco Necrosis Virus (TNV) is a small spherical virus about 280 A in diameter (Smith and Bald, 1934), consisting of 180 copies of coat protein and a single-stranded RNA with a molecular weight of about 1.3 x 10^6. It has been isolated with its satellite virus, Satellite Tobacco Necrosis Virus (STNV). STNV, about 200 A in diameter, consists of 60 copies of coat protein with a single-stranded RNA, and its crystal structure has been clarified at 2.5 A resolution (Jones and Liljas, 1984). STNV can multiply only with the assistance of its helper, TNV ; thus the functional and structural relationships between TNV and STNV are important from a virological viewpoint.X-ray intensity data for Tobacco Necrosis Virus (TNV) were obtained at 5 A resolution with a Weissenberg camera with a large cassette of 430 mm radius using synchrotron radiation at the Photon Factory. The icosahedral symmetry of the virus as well as packing of the virus particles in a unit cell were scrutinized by the rotation function. Assuming the subunit to be spherical, its arrangement on the icosahedral surface was determined by an R-factor search at 30 A resolution. The virus was found to be similar to southern bean mosaic virus in its subunit arrangement.Crystal structure was determined by the molecular replacement averaging. Electron density map at 5A resolution was obtained after about 100 cycles of the refinement starting at 8A resolution map. The final R-factor and correlation coefficient for the observed and calculated structure factors were 0.16 and 0.92, respectively. Model building of TNV is being carried out by using the map.

烟草坏死病毒（TNV）是一种直径约为280 A的小型球形病毒（Smith和Bald，1934），由180个拷贝的外壳蛋白和一个分子量约为1.3 x 10^6的单链RNA组成。该病毒与卫星烟草坏死病毒（Satellite Tobacco Necrosis Virus，STNV）一起分离。STNV直径约200 A，由60个拷贝的具有单链RNA的外壳蛋白组成，其晶体结构已在2.5 A分辨率下澄清（Jones和Liljas，1984）。STNV只能在其助手TNV的帮助下繁殖，因此TNV和STNV之间的功能和结构关系从病毒学的观点来看是重要的。烟草坏死病毒（TNV）的X射线强度数据在5 A分辨率下用具有430 mm半径的大暗盒的Weissenberg照相机在Photon Factory使用同步辐射获得。用旋转函数研究了病毒的二十面体对称性以及病毒颗粒在单位细胞中的堆积情况。假设亚基是球形的，其在二十面体表面上的排列通过在30 A分辨率下的R因子搜索来确定。该病毒的亚基排列与南方菜豆花叶病毒相似，晶体结构由分子置换平均法确定。在从8A分辨率图开始的约100个细化循环后，获得5A分辨率的电子密度图。观察到的和计算的结构因子的最终R因子和相关系数分别为0.16和0.92。TNV的模型建立正在通过使用地图进行。