Structure of a headful DNA-packaging bacterial virus at 2.9 Å resolution by electron cryo-microscopy
Structure of a headful DNA-packaging bacterial virus at 2.9 Å resolution by electron cryo-microscopy
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DOI：
10.1073/pnas.1615025114
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发表时间：
2017-04-04
影响因子：
11.1
通讯作者：
Tang, Liang
中科院分区：
文献类型：
--
作者：
Zhao, Haiyan;Li, Kunpeng;Tang, Liang
有尾DNA噬菌体在这个星球上的巨大流行是由数百个蛋白质亚基高效自组装成高度稳定的衣壳所实现的。由于噬菌体DNA包装过程，这些衣壳可以承受高达50个大气压的内部压力。在这里，我们报告完整的原子模型的头满的DNA包装噬菌体Sf6在2.9埃的分辨率由电子冷冻显微镜确定。该结构揭示了通过非共价相互作用组装的坚固蛋白质壳的DNA膨胀，紧张状态。衣壳蛋白的显著的全局构象多态性，由延伸的N臂、榫眼和榫状衣壳间接头和丰富的β-折叠状主链形成的网络：主链分子间相互作用，赋予衣壳组装和DNA包装所需的显著强度和灵活性。六邻体和五邻体的差异形成由剧烈的α-螺旋至β-链结构转变介导。这里揭示的装配方案可能是常见的尾DNA病毒和疱疹病毒。
The enormous prevalence of tailed DNA bacteriophages on this planet is enabled by highly efficient self-assembly of hundreds of protein subunits into highly stable capsids. These capsids can stand with an internal pressure as high as similar to 50 atmospheres as a result of the phage DNA-packaging process. Here we report the complete atomic model of the headful DNA-packaging bacteriophage Sf6 at 2.9 angstrom resolution determined by electron cryo-microscopy. The structure reveals the DNA-inflated, tensed state of a robust protein shell assembled via noncovalent interactions. Remarkable global conformational polymorphism of capsid proteins, a network formed by extended N arms, mortise-and-tenon-like intercapsomer joints, and abundant beta-sheet-like mainchain: mainchain intermolecular interactions, confers significant strength yet also flexibility required for capsid assembly and DNA packaging. Differential formations of the hexon and penton are mediated by a drastic alpha-helix-to-beta-strand structural transition. The assembly scheme revealed here may be common among tailed DNA phages and herpesviruses.