Real-time assembly landscape of bacterial 30S translation initiation complex
Real-time assembly landscape of bacterial 30S translation initiation complex
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DOI：
10.1038/nsmb.2285
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发表时间：
2012-06-01
影响因子：
16.8
通讯作者：
Rodnina, Marina V.
中科院分区：
文献类型：
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作者：
Milon, Pohl;Maracci, Cristina;Rodnina, Marina V.
起始因子引导核糖体选择mRNA和翻译阅读框架。我们确定了动力学上有利的装配途径的30 S preinitiation复合物（30 S PIC），在大肠杆菌中的30 S起始复合物形成的早期中间体。IF 3和IF 2是最先到达的因子，形成不稳定的30 S-IF 2-IF 3复合物。随后，IF 1将因子连接并锁定在动力学稳定的30 S PIC中，fMet-tRNA（fMet）被募集到该PIC中。mRNA的结合不依赖于起始因子，并且可以在30 S PIC组装期间的任何时间发生，这取决于mRNA的细胞浓度和核糖体结合位点处的结构决定簇。动力学分析显示了起始因子的特异性和累积效应以及在进入翻译时mRNA选择的动力学检查点。
Initiation factors guide the ribosome in the selection of mRNA and translational reading frame. We determined the kinetically favored assembly pathway of the 30S preinitiation complex (30S PIC), an early intermediate in 30S initiation complex formation in Escherichia coli. IF3 and IF2 are the first factors to arrive, forming an unstable 30S-IF2-IF3 complex. Subsequently, IF1 joins and locks the factors in a kinetically stable 30S PIC to which fMet-tRNA(fMet) is recruited. Binding of mRNA is independent of initiation factors and can take place at any time during 30S PIC assembly, depending on the cellular concentration of the mRNA and the structural determinants at the ribosome-binding site. The kinetic analysis shows both specific and cumulative effects of initiation factors as well as kinetic checkpoints of mRNA selection at the entry into translation.