A mechanical explanation of RNA pseudoknot function in programmed ribosomal frameshifting.
A mechanical explanation of RNA pseudoknot function in programmed ribosomal frameshifting.
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DOI：
10.1038/nature04735
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发表时间：
2006-05-11
期刊：
影响因子：
64.8
通讯作者：
Brierley I
中科院分区：
文献类型：
--
作者：
Namy O;Moran SJ;Stuart DI;Gilbert RJ;Brierley I
核糖体移码是许多病毒病原体复制过程中蛋白质合成的一种翻译机制，更广泛地说，是细胞基因的一种翻译机制。一组新的80 S核糖体在mRNA假结处停滞的图像显示了假结如何操纵核糖体进入不同的阅读框架。本文的在线版本（doi：10.1038/nature 04735）包含补充材料，可供授权用户使用。冷冻电子显微镜成像用于可视化在移码期间停滞的翻译核糖体。本文的在线版本（doi：10.1038/nature 04735）包含补充材料，可供授权用户使用。基于三联体的遗传密码要求翻译核糖体忠实地维持信使RNA的阅读框架，以确保正确的蛋白质合成。然而，在程序性-1核糖体移码中，发生了框架维持的特定颠覆，其中核糖体被迫将一个核苷酸向后移动到重叠的阅读框架中，并翻译全新的氨基酸序列。这一过程在许多病毒病原体的复制中是必不可少的，包括艾滋病毒和与严重急性呼吸系统综合征有关的冠状病毒，并且还在几种细胞基因的表达中被利用。移码由两个基本元件组成的mRNA信号促进：七核苷酸“滑动”序列和相邻的mRNA二级结构，最常见的是mRNA假结。这些成分如何一起操作核糖体尚不清楚。在这里，我们描述了一个核糖体-mRNA假结复合物的观察，是在-1移码的过程中停滞不前。从兔网织红细胞中纯化的哺乳动物80 S核糖体在冠状病毒假结处暂停的冷冻电子显微镜成像揭示了移码过程的中间体。由此可以看出假结如何与核糖体相互作用以阻断mRNA进入通道，损害易位过程并导致P位点转移RNA的弹簧样变形。此外，我们确定了可能的真核生物核糖体解旋酶的运动，并确认了移位酶eEF 2和P-位点tRNA之间的直接相互作用。总之，结构变化提供了一个机械解释如何假结操纵核糖体进入一个不同的阅读框架。本文的在线版本（doi：10.1038/nature 04735）包含补充材料，可供授权用户使用。
Ribosomal frameshifting is a translational mechanism involved in protein synthesis during the replication of many viral pathogens and in cellular genes more generally. A new set of images of an 80S ribosome stalled at an mRNA pseudoknot shows how the pseudoknot manipulates the ribosome into a different reading frame. The online version of this article (doi:10.1038/nature04735) contains supplementary material, which is available to authorized users. Cryoelectron microscopic imaging is used to visualize a translating ribosome stalled during frameshifting. The online version of this article (doi:10.1038/nature04735) contains supplementary material, which is available to authorized users. The triplet-based genetic code requires that translating ribosomes maintain the reading frame of a messenger RNA faithfully to ensure correct protein synthesis. However, in programmed -1 ribosomal frameshifting, a specific subversion of frame maintenance takes place, wherein the ribosome is forced to shift one nucleotide backwards into an overlapping reading frame and to translate an entirely new sequence of amino acids. This process is indispensable in the replication of numerous viral pathogens, including HIV and the coronavirus associated with severe acute respiratory syndrome, and is also exploited in the expression of several cellular genes. Frameshifting is promoted by an mRNA signal composed of two essential elements: a heptanucleotide ‘slippery’ sequence and an adjacent mRNA secondary structure, most often an mRNA pseudoknot. How these components operate together to manipulate the ribosome is unknown. Here we describe the observation of a ribosome–mRNA pseudoknot complex that is stalled in the process of -1 frameshifting. Cryoelectron microscopic imaging of purified mammalian 80S ribosomes from rabbit reticulocytes paused at a coronavirus pseudoknot reveals an intermediate of the frameshifting process. From this it can be seen how the pseudoknot interacts with the ribosome to block the mRNA entrance channel, compromising the translocation process and leading to a spring-like deformation of the P-site transfer RNA. In addition, we identify movements of the likely eukaryotic ribosomal helicase and confirm a direct interaction between the translocase eEF2 and the P-site tRNA. Together, the structural changes provide a mechanical explanation of how the pseudoknot manipulates the ribosome into a different reading frame. The online version of this article (doi:10.1038/nature04735) contains supplementary material, which is available to authorized users.
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影响因子：
64.5
作者：
Spahn, CMT;Beckmann, R;Frank, J
通讯作者：
Frank, J
影响因子：
64.5
作者：
Jacks T;Madhani HD;Masiarz FR;Varmus HE
通讯作者：
Varmus HE
影响因子：
5.3
作者：
Kontos, H;Napthine, S;Brierley, I
通讯作者：
Brierley, I
影响因子：
11.4
作者：
Spahn, CMT;Gomez-Lorenzo, MG;Frank, J
通讯作者：
Frank, J
DOI：
10.1038/nsb1003
发表时间：
2003-11-01
期刊：
NATURE STRUCTURAL BIOLOGY
影响因子：
--
作者：
Valle, M;Zavialov, A;Frank, J
通讯作者：
Frank, J