GTP-independent tRNA Delivery to the Ribosomal P-site by a Novel Eukaryotic Translation Factor
GTP-independent tRNA Delivery to the Ribosomal P-site by a Novel Eukaryotic Translation Factor
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DOI：
10.1074/jbc.m110.119693
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发表时间：
2010-08-27
影响因子：
4.8
通讯作者：
Shatsky, Ivan N.
中科院分区：
文献类型：
--
作者：
Dmitriev, Sergey E.;Terenin, Ilya M.;Shatsky, Ivan N.
在翻译过程中，氨酰-tRNAs被称为翻译因子的特殊GTP酶递送到核糖体。在这里，我们报道了从哺乳动物细胞中分离的一种新的GTP非依赖性因子eIF2D与40个S核糖体的P-位点结合的tRNA。TRNA(I)(Met)的结合发生在AUG密码子位于40个S核糖体的P位之后，这种情况发生在丙型肝炎病毒内部核糖体进入位点或其他一些特定RNA(无引线的mRNAs和扫描依赖松弛的富含A的mRNAs)上形成起始复合体的过程中。其与40个S亚基结合的活性不需要氨基酰基的存在。此外，该因子还具有独特的能力，将非Met(延伸物)tRNAs送入40个S亚基的P位。相应的基因在所有真核生物中都存在，并且包括一个也存在于翻译起始因子eIF1中的SUI1结构域。讨论了真核生物中翻译起始策略的多功能性。
During translation, aminoacyl-tRNAs are delivered to the ribosome by specialized GTPases called translation factors. Here, we report the tRNA binding to the P-site of 40 S ribosomes by a novel GTP-independent factor eIF2D isolated from mammalian cells. The binding of tRNA(i)(Met) occurs after the AUG codon finds its position in the P-site of 40 S ribosomes, the situation that takes place during initiation complex formation on the hepatitis C virus internal ribosome entry site or on some other specific RNAs (leaderless mRNA and A-rich mRNAs with relaxed scanning dependence). Its activity in tRNA binding with 40 S subunits does not require the presence of the aminoacyl moiety. Moreover, the factor possesses the unique ability to deliver non-Met (elongator) tRNAs into the P-site of the 40 S subunit. The corresponding gene is found in all eukaryotes and includes an SUI1 domain present also in translation initiation factor eIF1. The versatility of translation initiation strategies in eukaryotes is discussed.