STRUCTURE OF SATELLITE TOBACCO NECROSIS VIRUS AT 3.0 A RESOLUTION
STRUCTURE OF SATELLITE TOBACCO NECROSIS VIRUS AT 3.0 A RESOLUTION
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DOI：
10.1016/0022-2836(82)90033-x
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发表时间：
1982-01-01
影响因子：
5.6
通讯作者：
STRANDBERG, B
中科院分区：
文献类型：
--
作者：
LILJAS, L;UNGE, T;STRANDBERG, B
用X射线结晶学方法测定了卫星烟草坏死病毒(STNV)的结构，分辨率为3.0。利用粒子中60倍的非晶体对称性，得到了基于1个重原子导数的电子密度图和几个循环的相精化。利用计算机图形显示技术建立了1个蛋白质亚基的模型。亚基主要由形成2个β-片层的β-卷曲结构构成，每个β-片层由4条反平行的链组成。亚基的N-末端在3倍轴上形成3α-螺旋的束，延伸到病毒的RNA区域。多肽链的拓扑结构与番茄丛矮病毒(TBSV)和南方菜豆花叶病毒(SBMV)蛋白亚基的壳结构域相同，构象明显相似。然而，T=1 STNV结构中的亚基包装与这些T=3病毒的包装有显著不同：在STNV中，面对TBSV和SBMV中RNA的部分结构元件被用于亚基-亚基接触。在目前的二十面体平均电子密度图中没有明显的RNA结构。面对RNA的蛋白质表面主要含有亲水性残基，特别是赖氨酸和精氨酸。
The structure of satellite tobacco necrosis virus (STNV) was determined to 3.0 .ANG. resolution by X-ray crystallography. Electron density maps were obtained with phases based on 1 heavy-atom derivative and several cycles of phase refinement using the 60-fold non-crystallographic symmetry in the particle. A model for 1 protein subunit was built using a computer graphics display. The subunit is constructed mainly of a .beta.-roll structure forming 2 .beta.-sheets, each of 4 antiparallel strands. The N-termini of the subunits form bundles of 3 .alpha.-helices extending into the RNA region of the virus at the 3-fold axis. The topology of the polypeptide chain is the same as, and the conformation clearly similar to, that of the shell domains of the tomato bushy stunt virus (TBSV) and Southern bean mosaic virus (SBMV) protein subunits. The subunit packing in the T = 1 STNV structure is, however, significantly different from the packing of these T = 3 viruses: parts of some of the structural elements facing the RNA in TBSV and SBMV are utilized for subunit-subunit contacts in STNV. No RNA stucture is obvious in the present icosahedrally averaged electron density maps. The protein surface facing the RNA contains mainly hydrophilic residues, especially lysine and arginine.