The structure of Sinorhizobium meliloti phage ΦM12, which has a novel T=19l triangulation number and is the founder of a new group of T4-superfamily phages
The structure of Sinorhizobium meliloti phage ΦM12, which has a novel T=19l triangulation number and is the founder of a new group of T4-superfamily phages
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苜蓿中华根瘤菌噬菌体δM12的结构，其具有新颖的T=19l三角数，是新的T4超家族噬菌体群的创始人
DOI：
10.1016/j.virol.2013.11.019
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发表时间：
2014
期刊：
影响因子：
3.7
通讯作者：
Jones, Kathryn M.
中科院分区：
文献类型：
--
作者：
Stroupe, M. Elizabeth;Brewer, Tess E.;Sousa, Duncan R.;Jones, Kathryn M.
ΦM12是aT=19l几何衣壳的第一个例子，封装了最近测序的基因组。在这里，我们展示了通过冷冻电镜确定的完整衣壳和空衣壳的结构。该结构揭示了 1140 个 HK97 样衣壳蛋白的组装模式，指出了将不对称单元结合在一起的伪三重对称轴上的相互作用。衣壳特别光滑的表面，以及基因组编码的辅助外壳蛋白的缺乏，表明该界面是衣壳组装的主要机制。尾部（包括颈部和底板）的二维平均值表明，ΦM12 具有将尾部连接到衣壳的相对较窄的颈部以及三层底板。当没有 DNA 时，二十面体边缘扩大约 5 nm，而顶点保持在相同位置，形成类似光滑但弯曲的 T=19l 二十面体衣壳。
ΦM12 is the first example of aT=19l geometry capsid, encapsulating the recently sequenced genome. Here, we present structures determined by cryo-EM of full and empty capsids. The structure reveals the pattern for assembly of 1140 HK97-like capsid proteins, pointing to interactions at the pseudo 3-fold symmetry axes that hold together the asymmetric unit. The particular smooth surface of the capsid, along with a lack of accessory coat proteins encoded by the genome, suggest that this interface is the primary mechanism for capsid assembly. Two-dimensional averages of the tail, including the neck and baseplate, reveal that ΦM12 has a relatively narrow neck that attaches the tail to the capsid, as well as a three-layer baseplate. When free from DNA, the icosahedral edges expand by about 5 nm, while the vertices stay at the same position, forming a similarly smooth, but bowed,T=19l icosahedral capsid.