Atomic model of a cypovirus built from cryo-EM structure provides insight into the mechanism of mRNA capping
Atomic model of a cypovirus built from cryo-EM structure provides insight into the mechanism of mRNA capping
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由冷冻电镜结构构建的 Cypovirus 原子模型提供了对 mRNA 加帽机制的深入了解
DOI：
10.1073/pnas.1014995108
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发表时间：
2011-01-25
影响因子：
11.1
通讯作者：
Zhu, Ping
中科院分区：
文献类型：
--
作者：
Cheng, Lingpeng;Sun, Jingchen;Zhu, Ping
呼肠孤病毒科的细胞质多角体病毒(CPV)属于转角型呼肠孤病毒的一个亚群，其信使核糖核酸的封顶活动发生在五聚体转塔中。我们报道了用低温电子显微镜获得的三维密度图建立的CPV的完整原子模型。用于3D重建的图像数据完全从一台CCD摄像机获取。我们的结构表明，CPV五聚体转塔的酶结构域在拓扑上是保守的，并且有五个独特的通道连接鸟苷酸转移酶和甲基转移酶区域。这种结构结构揭示了通道如何依次引导新生mRNA到炮塔中的鸟苷酸转移酶、7-N-甲基转移酶和2‘-O-甲基转移酶，经历高度协调的mRNA封顶活动。此外，通过对CPV衣壳蛋白VP5与120个大突起蛋白氨基酸序列的拟合，证实该突起蛋白是由CPV RNA片段7编码的。
The cytoplasmic polyhedrosis virus (CPV) from the family Reoviridae belongs to a subgroup of "turreted" reoviruses, in which the mRNA capping activity occurs in a pentameric turret. We report a full atomic model of CPV built from a 3D density map obtained using cryoelectron microscopy. The image data for the 3D reconstruction were acquired exclusively from a CCD camera. Our structure shows that the enzymatic domains of the pentameric turret of CPV are topologically conserved and that there are five unique channels connecting the guanylyltransferase and methyltransferase regions. This structural organization reveals how the channels guide nascent mRNA sequentially to guanylyltransferase, 7-N-methyltransferase, and 2'-O-methyltransferase in the turret, undergoing the highly coordinated mRNA capping activity. Furthermore, by fitting the deduced amino acid sequence of the protein VP5 to 120 large protrusion proteins on the CPV capsid shell, we confirmed that this protrusion protein is encoded by CPV RNA segment 7.