Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Center for Infectious Disease Research, Department of Basic Medical Sciences, School of Medicine, Tsinghua University, 100084, Beijing, China.
Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule Zürich, CH-8093, Zürich, Switzerland.
Nat Commun. 2019 May 30;10(1):2366. doi: 10.1038/s41467-019-10272-3.
The mature virion of the tailed bacteriophage ϕ29 is an ~33 MDa complex that contains more than 450 subunits of seven structural proteins assembling into a prolate head and a short non-contractile tail. Here, we report the near-atomic structures of the ϕ29 pre-genome packaging head (prohead), the mature virion and the genome-emptied virion. Structural comparisons suggest local rotation or oscillation of the head-tail connector upon DNA packaging and release. Termination of the DNA packaging occurs through pressure-dependent correlative positional and conformational changes in the connector. The funnel-shaped tail lower collar attaches the expanded narrow end of the connector and has a 180-Å long, 24-strand β barrel narrow stem tube that undergoes conformational changes upon genome release. The appendages form an interlocked assembly attaching the tail around the collar. The membrane active long loops at the distal end of the tail knob exit during the late stage of infection and form the cone-shaped tip of a largely hydrophobic helix barrel, prepared for membrane penetration.
长尾噬菌体 φ29 的成熟病毒体是一个约 33MDa 的复杂结构，包含超过 450 个七种结构蛋白的亚基，这些亚基组装成一个长而扁的头部和一个短的非收缩尾部。在这里，我们报告了 φ29 前基因组包装头（原头）、成熟病毒体和基因组排空病毒体的近原子结构。结构比较表明，在 DNA 包装和释放过程中，头部-尾部连接器会发生局部旋转或摆动。DNA 包装的终止是通过连接器中压力相关的位置和构象变化来实现的。漏斗形尾部下环附着在连接器的扩展的窄端，并具有一个 180-Å 长的 24 股 β 桶窄管，在基因组释放时发生构象变化。附属物形成一个互锁组件，将尾部固定在环上。尾部末端的膜活性长环在感染的晚期离开，并形成一个大的疏水性螺旋桶的锥形尖端，为膜穿透做好准备。
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