Cryo-EM asymmetric reconstruction of bacteriophage P22 reveals organization of its DNA packaging and infecting machinery
Cryo-EM asymmetric reconstruction of bacteriophage P22 reveals organization of its DNA packaging and infecting machinery
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DOI：
10.1016/j.str.2006.05.007
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发表时间：
2006-06-01
期刊：
影响因子：
5.7
通讯作者：
Jiang, Wen
中科院分区：
文献类型：
--
作者：
Chang, Juan;Weigele, Peter;Jiang, Wen
大多数双链DNA病毒包装和释放其基因组DNA的机制尚不完全清楚。单颗粒冷冻电子显微镜和不对称三维重建揭示了完整的噬菌体P22病毒粒子的组织，包括DNA最初被包装和随后被排出的蛋白质通道。这个通道是由门户蛋白的十二聚体形成的，并由一个尾部枢纽密封，尾部枢纽由两个堆叠的桶组成，上面有一根蛋白针。连接在这个尾部枢纽周围的六个三聚体尾刺是扭曲的，这表明一个功能铰链可能被用来触发DNA释放。在衣壳内，门户的中央通道被解释为引导/注射蛋白的密度堵塞。靠近这些蛋白质的短杆状密度可能是dsDNA基因组的末端片段。同轴包装的DNA基因组被二十面体外壳包裹。这种完整的结构统一了过去几十年来其成分的各种生化、遗传和结晶学数据。
The mechanisms by which most double-stranded DNA viruses package and release their genomic DNA are not fully understood. Single particle cryo-electron microscopy and asymmetric 3D reconstruction reveal the organization of the complete bacteriophage P22 virion, including the protein channel through which DNA is first packaged and later ejected. This channel is formed by a dodecamer of portal proteins and sealed by a tail hub consisting of two stacked barrels capped by a protein needle. Six trimeric tailspikes attached around this tail hub are kinked, suggesting a functional hinge that may be used to trigger DNA release. Inside the capsid, the portal's central channel is plugged by densities interpreted as pilot/injection proteins. A short rod-like density near these proteins may be the terminal segment of the dsDNA genome. The coaxially packed DNA genome is encapsidated by the icosahedral shell. This complete structure unifies various biochemical, genetic, and crystallographic data of its components from the past several decades.