GTP-independent tRNA Delivery to the Ribosomal P-site by a Novel Eukaryotic Translation Factor |
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Authors: | Sergey E. Dmitriev Ilya M. Terenin Dmitri E. Andreev Pavel A. Ivanov Jacov E. Dunaevsky William C. Merrick Ivan N. Shatsky |
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Affiliation: | From the ‡Belozersky Institute of Physico-Chemical Biology and ;§Faculty of Biology, Moscow State University, Moscow 119992, Russia and ;the ¶Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106 |
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Abstract: | 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 tRNAiMet 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. |
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Keywords: | Ribosome Function RNA RNA Viruses Translation Initiation Factors Translation Regulation Hepatitis C Virus SUI1 Domain eIF2A eIF2D Ligatin |
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