Coupling of ribosomal L1 stalk and tRNA dynamics during translation elongation
Coupling of ribosomal L1 stalk and tRNA dynamics during translation elongation
复制标题
DOI：
10.1016/j.molcel.2008.03.012
复制
发表时间：
2008-05-09
期刊：
影响因子：
16
通讯作者：
Gonzalez, Ruben L., Jr.
中科院分区：
文献类型：
--
作者：
Fei, Jingyi;Kosuri, Pallav;Gonzalez, Ruben L., Jr.
通过单分子荧光共振能量转移(SmFRET)，我们观察到标记在L1茎上的核糖体与转移RNA(TRNA)之间的实时动态耦合。我们发现，核糖体L1茎和新脱酰化的tRNA之间的相互作用是在肽键形成的基础上自发建立的；这一事件涉及L1茎和tRNA的耦合运动以及核糖体的棘轮。在没有伸长因子G的情况下，整个预易位核糖体只在两种状态之间波动：非棘状状态，tRNA处于经典构型，没有L1柄-tRNA相互作用；棘状状态，tRNA处于中间杂交构型，直接L1柄-tRNA相互作用。我们证明了EF-G的结合使平衡向棘齿态移动。实时smFRET实验表明，L1茎与tRNA的相互作用在整个易位反应中持续，表明L1茎在易位过程中指导tRNA运动。
By using single-molecule fluorescence resonance energy transfer (smFRET), we observe the real-time dynamic coupling between the ribosome, labeled at the L1 stalk, and transfer RNA (tRNA). We find that an interaction between the ribosomal L1 stalk and the newly deacylated tRNA is established spontaneously upon peptide bond formation; this event involves coupled movements of the L1 stalk and tRNAs as well as ratcheting of the ribosome. In the absence of elongation factor G, the entire pretranslocation ribosome fluctuates between just two states: a nonratcheted state, with tRNAs in their classical configuration and no L1 stalk-tRNA interaction, and a ratcheted state, with tRNAs in an intermediate hybrid configuration and a direct L1 stalk-tRNA interaction. We demonstrate that binding of EF-G shifts the equilibrium toward the ratcheted state. Real-time smFRET experiments reveal that the L1 stalk-tRNA interaction persists throughout the translocation reaction, suggesting that the L1 stalk acts to direct tRNA movements during translocation.