Structural basis for the recognition of guide RNA and target DNA heteroduplex by Argonaute.
Structural basis for the recognition of guide RNA and target DNA heteroduplex by Argonaute.
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DOI：
10.1038/ncomms11846
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发表时间：
2016-06-21
影响因子：
16.6
通讯作者：
Uchiumi T
中科院分区：
文献类型：
--
作者：
Miyoshi T;Ito K;Murakami R;Uchiumi T
Argonaute 蛋白是从细菌到真核生物的所有生命领域中由小核酸介导的基因沉默机制的关键参与者。然而，人们对识别引导 RNA/目标 DNA 的 Argonaute 蛋白知之甚少。在这里，我们确定了球形红杆菌 Argonaute (RsAgo) 与 18 核苷酸引导 RNA 及其互补靶 DNA 的复合物中的 2 Å 晶体结构。即使在 N 端和 PIWI 结构域之间的向导 RNA 的 3' 区，异源双链体也能保持 Watson-Crick 碱基配对，这表明 RsAgo 具有与目标链稳定相互作用的识别模式。此外，RsAgo的MID/PIWI接口具有特异性识别向导RNA的5'碱基U的系统，PAZ结构域的双链体识别环对于DNA沉默活性很重要。此外，我们表明 Argonaute 通过识别种子区域的双链体结构来区分核酸类型（RNA/DNA）。 Argonaute 蛋白在一些调节 RNA 的沉默机制中发挥着重要作用。在这里，作者解析了与引导 RNA 和目标 DNA 复合的 argonaute 蛋白的结构，并提出了一种识别它们的机制。
Argonaute proteins are key players in the gene silencing mechanisms mediated by small nucleic acids in all domains of life from bacteria to eukaryotes. However, little is known about the Argonaute protein that recognizes guide RNA/target DNA. Here, we determine the 2 Å crystal structure of Rhodobacter sphaeroides Argonaute (RsAgo) in a complex with 18-nucleotide guide RNA and its complementary target DNA. The heteroduplex maintains Watson–Crick base-pairing even in the 3′-region of the guide RNA between the N-terminal and PIWI domains, suggesting a recognition mode by RsAgo for stable interaction with the target strand. In addition, the MID/PIWI interface of RsAgo has a system that specifically recognizes the 5′ base-U of the guide RNA, and the duplex-recognition loop of the PAZ domain is important for the DNA silencing activity. Furthermore, we show that Argonaute discriminates the nucleic acid type (RNA/DNA) by recognition of the duplex structure of the seed region. Argonaute proteins are important in the silencing machinery with some regulatory RNAs. Here, the authors solve the structure of an argonaute protein in complex with both the guide RNA and target DNA and propose a mechanism for their recognition.