Following translation by single ribosomes one codon at a time
Following translation by single ribosomes one codon at a time
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DOI：
10.1038/nature06716
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发表时间：
2008-04-03
期刊：
影响因子：
64.8
通讯作者：
Tinoco, Ignacio, Jr.
中科院分区：
文献类型：
--
作者：
Wen, Jin-Der;Lancaster, Laura;Tinoco, Ignacio, Jr.
我们已经跟踪了单个核糖体，因为它们将末端拴在光学镊子上的单个信使RNA发夹翻译。在这里，我们揭示了翻译发生通过连续的易位和暂停周期。停顿长度的分布，中位数为2.8秒，表明至少有两个速率决定过程控制每个停顿。每个易位步骤测量三个碱基-一个密码子-并且在小于0.1秒内发生。令人惊讶的是，对易位所需时间的分析揭示了每个步骤中有三个子步骤。翻译的长度，因此总的翻译速率，取决于mRNA的二级结构;所施加的力使二级结构不稳定，并减少停顿时间，但不影响易位时间。易位和RNA解旋是严格耦合的核糖体功能。
We have followed individual ribosomes as they translate single messenger RNA hairpins tethered by the ends to optical tweezers. Here we reveal that translation occurs through successive translocation- and- pause cycles. The distribution of pause lengths, with a median of 2.8 s, indicates that at least two rate- determining processes control each pause. Each translocation step measures three bases - one codon - and occurs in less than 0.1 s. Analysis of the times required for translocation reveals, surprisingly, that there are three substeps in each step. Pause lengths, and thus the overall rate of translation, depend on the secondary structure of the mRNA; the applied force destabilizes secondary structure and decreases pause durations, but does not affect translocation times. Translocation and RNA unwinding are strictly coupled ribosomal functions.