Crystal Structure of the Superfamily 1 Helicase from Tomato Mosaic Virus
Crystal Structure of the Superfamily 1 Helicase from Tomato Mosaic Virus
复制标题
DOI：
10.1128/jvi.00118-12
复制
发表时间：
2012-07-01
影响因子：
5.4
通讯作者：
Katoh, Etsuko
中科院分区：
文献类型：
--
作者：
Nishikiori, Masaki;Sugiyama, Shigeru;Katoh, Etsuko
番茄花叶病毒和许多其他植物和动物正链RNA病毒的基因组编码超家族1解旋酶。尽管解旋酶在病毒复制中起重要作用，但病毒超家族1解旋酶的晶体结构尚未确定。在这里，我们报告的晶体结构的片段（S666至Q1116）的复制蛋白从番茄花叶病毒。该结构揭示了一种新的N-末端结构域与解旋酶核心紧密相关。解旋酶核心含有两个RecA样α/β结构域，而没有在其他超家族1解旋酶中发现的任何附属结构域插入。N-末端结构域包含柔性环、长α-螺旋和反平行六链β-折叠。基于该结构，我们构建了S666-Q1116片段的缺失突变体，并在酿酒酵母中与番茄花叶病毒RNA复制所必需的宿主蛋白TOM 1和ARL 8进行了基于分裂泛素的相互作用测定。结果表明，TOM 1和ARL 8都与N-末端结构域中的长α-螺旋相互作用，TOMI也与解旋酶核心相互作用。预测其他病毒超家族1解旋酶的二级结构，并将这些结构与S666-to-Q1116结构进行比较，表明这些解旋酶具有相似的折叠。我们的研究结果提供了病毒超家族1解旋酶的结构基础。
The genomes of the Tomato mosaic virus and many other plant and animal positive-strand RNA viruses of agronomic and medical importance encode superfamily 1 helicases. Although helicases play important roles in viral replication, the crystal structures of viral superfamily 1 helicases have not been determined. Here, we report the crystal structure of a fragment (S666 to Q1116) of the replication protein from Tomato mosaic virus. The structure reveals a novel N-terminal domain tightly associated with a helicase core. The helicase core contains two RecA-like alpha/beta domains without any of the accessory domain insertions that are found in other superfamily 1 helicases. The N-terminal domain contains a flexible loop, a long a-helix, and an antiparallel six-stranded beta-sheet. On the basis of the structure, we constructed deletion mutants of the S666-to-Q1116 fragment and performed split-ubiquitin-based interaction assays in Saccharomyces cerevisiae with TOM1 and ARL8, host proteins that are essential for tomato mosaic virus RNA replication. The results suggested that both TOM1 and ARL8 interact with the long a-helix in the N-terminal domain and that TOMI also interacts with the helicase core. Prediction of secondary structures in other viral superfamily 1 helicases and comparison of those structures with the S666-to-Q1116 structure suggested that these helicases have a similar fold. Our results provide a structural basis of viral superfamily 1 helicases.