The structure of simian virus 40 refined at 3.1 angstrom resolution
The structure of simian virus 40 refined at 3.1 angstrom resolution
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DOI：
10.1016/s0969-2126(96)00020-2
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发表时间：
1996-02-15
期刊：
影响因子：
5.7
通讯作者：
Harrison, SC
中科院分区：
文献类型：
--
作者：
Stehle, T;Gamblin, SJ;Harrison, SC
背景资料：猴病毒40（SV40）的结构，先前在3.8埃分辨率下确定，显示了其五聚体VP1组装单元如何通过延伸的C末端臂连接在一起。为了更精确地定义可能的组装机制，我们已经改进了结构在3.1埃resolution.Results：新的数据从高强度同步辐射源已被用于相位扩展的电子密度平均和细化，利用只有严格的5倍非晶体对称性的真实空间平均步骤。精确的模型使我们能够详细研究病毒颗粒的重要结构特征。VP1五聚体的显著不变的核心具有来自其他五聚体的C末端臂的对接位点。这些接触是五聚体组装单元在衣壳中连接在一起的主要方式。只有在五配位和六配位五聚体之间的界面处，五聚体核心才表现出强烈的相互作用。每个VP1单体有两个阳离子结合位点，在硝酸钆的浸泡实验中可以看到。这些网站是相当接近彼此之间的界面pentameres.Conclusions：我们建议，五配位和六配位的五聚体之间的接触可能有助于产生一个六五聚体核，进一步的五聚体可以组装，以产生完整的粒子。钙离子可能稳定了组装粒子的结构，而不是指导其组装。
Background: The structure of simian virus 40 (SV40), previously determined at 3.8 Angstrom resolution, shows how its pentameric VP1 assembly units are tied together by extended C-terminal arms. In order to define more precisely the possible assembly mechanisms, we have refined the structure at 3.1 Angstrom resolution.Results: New data from a high-intensity synchrotron source have been used for phase extension by electron-density averaging and refinement, exploiting only the strict 5-fold non-crystallographic symmetry for the real-space averaging steps. The accurate model enables us to study important structural features of the virus particle in detail. The remarkably invariant core of the VP1 pentamer bears the docking sites for the C-terminal arms from other pentamers. These contacts are the principal way in which pentameric assembly units are linked together in the capsid. Only at the interface between five-coordinated and six-coordinated pentamers do the pentamer cores appear to interact strongly. There are two cation-binding sites per VP1 monomer, seen in a soaking experiment with gadolinium nitrate. These sites are quite close to each other at the interfaces between pentamers.Conclusions: We propose that the contact between five-coordinated and six-coordinated pentamers may help to generate a six-pentamer nucleus, with which further pentamers can assemble to generate the complete particle. Calcium ions probably stabilize the structure of the assembled particle, rather than direct its assembly.