RNA silencing suppressor p21 of Beet yellows virus forms an RNA binding octameric ring structure.
RNA silencing suppressor p21 of Beet yellows virus forms an RNA binding octameric ring structure.
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DOI：
10.1016/j.str.2005.06.017
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发表时间：
2005-09
期刊：
影响因子：
5.7
通讯作者：
K. Ye;D. Patel
中科院分区：
文献类型：
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作者：
K. Ye;D. Patel
许多植物病毒编码的蛋白质可抑制宿主发起的抗病毒 RNA 沉默反应。来自 tombusvirus 的抑制因子 p19 和来自甜菜黄化病毒的 p21 抑制因子似乎通过直接结合 siRNA（该过程中的关键介质）来阻止沉默。在这里，我们报告了 p21 的晶体结构，它揭示了八聚环结构，具有直径约 90 Å 的大中心空腔。全 α 螺旋 p21 单体由 N 端和 C 端结构域组成，这些结构域通过对称的头对头和尾对尾相互作用与其相邻对应物相关联。在环的保守、带正电荷的内表面中鉴定出推定的RNA结合表面。与特定的 p19-siRNA 双链体相互作用相反，p21 是一种通用的核酸结合蛋白，在体外与 21 nt 或更长的单链和双链 RNA 相互作用。这项研究揭示了 p21 沉默抑制子采用的 RNA 结合结构。
Many plant viruses encode proteins that suppress the antiviral RNA silencing response mounted by the host. The suppressors p19 from tombusvirus and p21 from Beet yellows virus appear to block silencing by directly binding siRNA, a critical mediator in the process. Here, we report the crystal structure of p21, which reveals an octameric ring architecture with a large central cavity of ∼90 Å diameter. The all α-helical p21 monomer consists of N- and C-terminal domains that associate with their neighboring counterparts through symmetric head-to-head and tail-to-tail interactions. A putative RNA binding surface is identified in the conserved, positive-charged inner surface of the ring. In contrast to the specific p19-siRNA duplex interaction, p21 is a general nucleic acid binding protein, interacting with 21 nt or longer single- and double-stranded RNAs in vitro. This study reveals an RNA binding structure adopted by the p21 silencing suppressor.