The ribosome-bound initiation factor 2 recruits initiator tRNA to the 30S initiation complex
The ribosome-bound initiation factor 2 recruits initiator tRNA to the 30S initiation complex
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DOI：
10.1038/embor.2010.12
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发表时间：
2010-04-01
期刊：
影响因子：
7.7
通讯作者：
Gualerzi, Claudio O.
中科院分区：
文献类型：
--
作者：
Milon, Pohl;Carotti, Marcello;Gualerzi, Claudio O.
细菌翻译起始因子2 （IF2）是一种促进启动物fMet- trna （fMet）与30S核糖体亚基结合的GTPase。通常假设IF2在三元复合物IF2中将fMet- trna （fMet）传递给核糖体。三磷酸鸟苷。fMet-tRNA (fMet)。通过使用快速动力学技术，我们在这里证明了IF2的结合。GTP到达30S核糖体亚基之前，独立于fMet- trna （fMet）结合。IF2在溶液中形成的三元络合物。GTP和fMet-tRNA是不稳定的，在IF2之前解离。GTP和随后的fMet- trna （fMet）结合到30S亚基上。核糖体结合的IF2可能通过提供锚定相互作用或诱导有利的核糖体构象来加速fMet- trna （fMet）向30S起始复合物的招募。IF2的作用机制似乎与tRNA载体如EF-Tu、SelB和真核起始因子2 （eIF2）不同，而与真核亚基结合因子eIF5B相似。
Bacterial translation initiation factor 2 (IF2) is a GTPase that promotes the binding of the initiator fMet-tRNA(fMet) to the 30S ribosomal subunit. It is often assumed that IF2 delivers fMet-tRNA(fMet) to the ribosome in a ternary complex, IF2. GTP. fMet-tRNA(fMet). By using rapid kinetic techniques, we show here that binding of IF2. GTP to the 30S ribosomal subunit precedes and is independent of fMet-tRNA(fMet) binding. The ternary complex formed in solution by IF2. GTP and fMet-tRNA is unstable and dissociates before IF2. GTP and, subsequently, fMet-tRNA(fMet) bind to the 30S subunit. Ribosome-bound IF2 might accelerate the recruitment of fMet-tRNA(fMet) to the 30S initiation complex by providing anchoring interactions or inducing a favourable ribosome conformation. The mechanism of action of IF2 seems to be different from that of tRNA carriers such as EF-Tu, SelB and eukaryotic initiation factor 2 (eIF2), instead resembling that of eIF5B, the eukaryotic subunit association factor.