Structural basis for messenger RNA movement on the ribosome
Structural basis for messenger RNA movement on the ribosome
复制标题
DOI：
10.1038/nature05281
复制
发表时间：
2006-11-16
期刊：
影响因子：
64.8
通讯作者：
Yusupov, Marat
中科院分区：
文献类型：
--
作者：
Yusupova, Gulnara;Jenner, Lasse;Yusupov, Marat
翻译起始是基因整体表达水平的主要决定因素(1 - 3)。功能活性蛋白的翻译需要将信使 RNA 定位在核糖体上，以便首先以正确的读框读取起始密码子。对于不同翻译状态下 mRNA 与核糖体相互作用的分子基础知之甚少。最近的核糖体亚基 (4 - 8)、空 70S 核糖体 (9) 和含有功能配体的 70S 核糖体 (10 - 13) 的晶体结构提供了有关核糖体及其功能中心的一般组织的信息。在这里，我们比较了八个核糖体复合物的 X 射线结构，模拟了翻译起始、起始后和延伸状态。在起始和起始后复合物中，Shine-Dalgarno (SD) 双链体的存在导致 mRNA 5' 末端牢固锚定到 30S 亚基的平台上，从而在 mRNA 和核糖体之间产生大量相互作用。相反，缺乏 SD 相互作用的“延伸器”mRNA 的 5' 端是灵活的，表明延伸过程中 mRNA 的退出路径不同。翻译开始后，当 SD 相互作用仍然存在时，mRNA 沿 3'->5' 方向移动，同时顺时针旋转并延长 SD 双链体，使其与核糖体蛋白 S2 接触。
Translation initiation is a major determinant of the overall expression level of a gene(1 - 3). The translation of functionally active protein requires the messenger RNA to be positioned on the ribosome such that the start/ initiation codon will be read first and in the correct frame. Little is known about the molecular basis for the interaction of mRNA with the ribosome at different states of translation. Recent crystal structures of the ribosomal subunits(4 - 8), the empty 70S ribosome(9) and the 70S ribosome containing functional ligands(10 - 13) have provided information about the general organization of the ribosome and its functional centres. Here we compare the X- ray structures of eight ribosome complexes modelling the translation initiation, post- initiation and elongation states. In the initiation and post- initiation complexes, the presence of the Shine - Dalgarno ( SD) duplex causes strong anchoring of the 5' end of mRNA onto the platform of the 30S subunit, with numerous interactions between mRNA and the ribosome. Conversely, the 5' end of the ' elongator' mRNA lacking SD interactions is flexible, suggesting a different exit path for mRNA during elongation. After the initiation of translation, but while an SD interaction is still present, mRNA moves in the 3' -->5' direction with simultaneous clockwise rotation and lengthening of the SD duplex, bringing it into contact with ribosomal protein S2.