Following movement of the L1 stalk between three functional states in single ribosomes
Following movement of the L1 stalk between three functional states in single ribosomes
复制标题
DOI：
10.1073/pnas.0813180106
复制
发表时间：
2009-02-24
影响因子：
11.1
通讯作者：
Ha, Taekjip
中科院分区：
文献类型：
--
作者：
Cornish, Peter V.;Ermolenko, Dmitri N.;Ha, Taekjip
L1茎是核糖体大亚基E位点的一个移动的结构域，在蛋白质合成过程中与脱酰化tRNA手肘相互作用。在这里，通过使用单分子FRET，我们跟随L1柄的实时动态，并观察其相对于大亚基的身体在至少3种不同的构象状态之间的运动：开放，半封闭和完全封闭。易位前核糖体在开放和完全闭合状态之间进行自发波动。与此相反，含有肽基tRNA和脱酰tRNA的posttranslocation核糖体在经典的P/P和E/E状态，分别固定在半封闭构象。在核糖体与一个空缺的E位点，L1柄观察到无论是在完全关闭或完全打开的构象。一些证据表明，L1柄可以独立于亚基间旋转移动。我们的研究结果支持一个模型，其中的L1柄的流动性有利于结合，运动和释放脱酰tRNA的重塑之间的3个不同的构象，对应于E/E空，P/E混合，和经典状态的50 S亚基E网站的结构。
The L1 stalk is a mobile domain of the large ribosomal subunit E site that interacts with the elbow of deacylated tRNA during protein synthesis. Here, by using single-molecule FRET, we follow the real-time dynamics of the L1 stalk and observe its movement relative to the body of the large subunit between at least 3 distinct conformational states: open, half-closed, and fully closed. Pretranslocation ribosomes undergo spontaneous fluctuations between the open and fully closed states. In contrast, posttranslocation ribosomes containing peptidyl-tRNA and deacylated tRNA in the classical P/P and E/E states, respectively, are fixed in the half-closed conformation. In ribosomes with a vacant E site, the L1 stalk is observed either in the fully closed or fully open conformation. Several lines of evidence show that the L1 stalk can move independently of intersubunit rotation. Our findings support a model in which the mobility of the L1 stalk facilitates binding, movement, and release of deacylated tRNA by remodeling the structure of the 50S subunit E site between 3 distinct conformations, corresponding to the E/E vacant, P/E hybrid, and classical states.