Crystal structure of argonaute and its implications for RISC slicer activity
Crystal structure of argonaute and its implications for RISC slicer activity
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DOI：
10.1126/science.1102514
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发表时间：
2004-09-03
期刊：
影响因子：
56.9
通讯作者：
Joshua-Tor, L
中科院分区：
文献类型：
--
作者：
Song, JJ;Smith, SK;Joshua-Tor, L
Argonaute蛋白和小干扰RNA（siRNA）是RNA干扰效应复合物RNA诱导沉默复合物（RISC）的已知标志性成分。然而，按照siRNA的指令切割信使RNA（mRNA）的酶“Slicer”的身份尚未确定。在此，我们报道了激烈火球菌（Pyrococcus furiosus）的Argonaute蛋白在2.25埃分辨率下的晶体结构。该结构显示出一个由氨基末端、中间和PIWI结构域组成的新月形基部。Piwi Argonaute Zwille（PAZ）结构域通过一个“茎”状区域支撑在基部上方。PIWI结构域（以piwi蛋白命名）类似于核糖核酸酶H，具有保守的活性位点天冬氨酸 - 天冬氨酸 - 谷氨酸基序，这强烈暗示Argonaute就是“Slicer”。分子的结构以及PAZ和PIWI结构域的位置确定了一个底物结合凹槽，并提出了一种siRNA引导的mRNA切割机制。
Argonaute proteins and small interfering RNAs (siRNAs) are the known signature components of the RNA interference effector complex RNA-induced silencing complex (RISC). However, the identity of "Slicer," the enzyme that cleaves the messenger RNA (mRNA) as directed by the siRNA, has not been resolved. Here, we report the crystal structure of the Argonaute protein from Pyrococcus furiosus at 2.25 angstrom resolution. The structure reveals a crescent-shaped base made up of the amino-terminal, middle, and PIWI domains. The Piwi Argonaute Zwille (PAZ) domain is held above the base by a "stalk"-like region. The PIWI domain (named for the protein piwi) is similar to ribonuclease H, With a conserved active site aspartate-aspartate-glutamate motif, strongly implicating Argonaute as "Slicer." The architecture of the molecule and the placement of the PAZ and PIWI domains define a groove for substrate binding and suggest a mechanism for siRNA-guided mRNA cleavage.