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Recognition of small interfering RNA by a viral suppressor of RNA silencing

机译:RNA沉默的病毒抑制器识别小干扰RNA

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摘要

RNA silencing (also known as RNA interference) is a conserved biological response to double-stranded RNA that regulates gene expression, and has evolved in plants as a defence against viruses. The response is mediated by small interfering RNAs (siRNAs), which guide the sequence-specific degradation of cognate messenger RNAs. As a counter-defence, many viruses encode proteins that specifically inhibit the silencing machinery. The p19 protein from the tombusvirus is such a viral suppressor of RNA silencing and has been shown to bind specifically to siRNA. Here, we report the 1.85-A crystal structure of p19 bound to a 21-nucleotide siRNA, where the 19-base-pair RNA duplex is cradled within the concave face of a continuous eight-stranded β-sheet, formed across the p19 homodimer interface. Direct and water-mediated intermolecular contacts are restricted to the backbone phosphates and sugar 2′-OH groups, consistent with sequence-independent p19-siRNA recognition. Two α-helical 'reading heads' project from opposite ends of the p19 homodimer and position pairs of tryptophans for stacking over the terminal base pairs, thereby measuring and bracketing both ends of the siRNA duplex. Our structure provides an illustration of siRNA sequestering by a viral protein.
机译:RNA沉默(也称为RNA干扰)是对调节基因表达的双链RNA的保守生物学反应,已在植物中进化为防御病毒。该反应由小干扰RNA(siRNA)介导,该RNA指导同源信使RNA的序列特异性降解。为了防御,许多病毒编码的蛋白质会特异性抑制沉默机制。鼓膜病毒的p19蛋白是这种RNA沉默的病毒抑制剂,并且已显示与siRNA特异性结合。在这里,我们报告了p19的1.85-A晶体结构与21个核苷酸的siRNA结合的情况,其中19个碱基对的RNA双链体在横跨p19同二聚体形成的连续八链β-折叠的凹面内形成。接口。直接和水介导的分子间接触仅限于骨架磷酸酯和糖2'-OH基团,这与序列独立的p19-siRNA识别相一致。从p19同型二聚体的相对两端和色氨酸的位置对伸出两个α螺旋“读数头”,以堆叠在末端碱基对上,从而测量并包围siRNA双链体的两端。我们的结构提供了病毒蛋白隔离siRNA的例证。

著录项

  • 来源
    《Nature》 |2003年第6968期|p.874-878|共5页
  • 作者单位

    Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 自然科学总论;
  • 关键词

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