GTP-independent tRNA Delivery to the Ribosomal P-site by a Novel Eukaryotic Translation Factor

作者：Dmitriev Sergey E; Terenin Ilya M; Andreev Dmitri E; Ivanov Pavel A; Dunaevsky Jacov E; Merrick William C; Shatsky Ivan N^*

来源：JOURNAL OF BIOLOGICAL CHEMISTRY, 2010, 285(35): 26779-26787.

DOI：10.1074/jbc.M110.119693

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.

• 出版日期2010-8-27