title: Stabilization of eukaryotic ribosomal termination complexes by deacylated tRNA.
abstract: Stabilization of the ribosomal complexes plays an important role in translational control. Mechanisms of ribosome stabilization have been studied in detail for initiation and elongation of eukaryotic translation, but almost nothing is known about stabilization of eukaryotic termination ribosomal complexes. Here, we present one of the mechanisms of fine-tuning of the translation termination process in eukaryotes. We show that certain deacylated tRNAs, remaining in the E site of the ribosome at the end of the elongation cycle, increase the stability of the termination and posttermination complexes. Moreover, only the part of eRF1 recognizing the stop codon is stabilized in the A site of the ribosome, and the stabilization is not dependent on the hydrolysis of peptidyl-tRNA. The determinants, defining this property of the tRNA, reside in the acceptor stem. It was demonstrated by site-directed mutagenesis of tRNA(Val) and construction of a mini-helix structure identical to the acceptor stem of tRNA. The mechanism of this stabilization is different from the fixation of the unrotated state of the ribosome by CCA end of tRNA or by cycloheximide in the E site. Our data allow to reveal the possible functions of the isodecoder tRNAs in eukaryotes.
authors.affiliation: Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, 119991 Moscow, Russia Faculty of Bioengineering and Bioinformatics, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia.
authors.forename: Denis
authors.initials: D
authors.lastname: Susorov
authors.affiliation: Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, 119991 Moscow, Russia.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Mikhailova
authors.affiliation: Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, 119991 Moscow, Russia Faculty of Bioengineering and Bioinformatics, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia.
authors.forename: Alexander
authors.initials: A
authors.lastname: Ivanov
authors.affiliation: Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, 119991 Moscow, Russia.
authors.forename: Elizaveta
authors.initials: E
authors.lastname: Sokolova
authors.affiliation: Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, 119991 Moscow, Russia alkalaeva@eimb.ru.
authors.forename: Elena
authors.initials: E
authors.lastname: Alkalaeva
mesh_terms: D000215:Acylation; D000818:Animals; D018388:Codon, Terminator; D006801:Humans; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D009690:Nucleic Acid Conformation; D010443:Peptide Chain Termination, Translational; D010454:Peptide Termination Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D055550:Protein Stability; D020871:RNA Stability; D012343:RNA, Transfer / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012366:RNA, Transfer, Val / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011817:Rabbits; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism*
chemical_list: D018388:Codon, Terminator; D010454:Peptide Termination Factors; D012366:RNA, Transfer, Val; D011994:Recombinant Proteins; D012343:RNA, Transfer