title: A central fragment of ribosomal protein S26 containing the eukaryote-specific motif YxxPKxYxK is a key component of the ribosomal binding site of mRNA region 5' of the E site codon.
abstract: The eukaryotic ribosomal protein S26e (rpS26e) lacking eubacterial counterparts is a key component of the ribosomal binding site of mRNA region 5' of the codon positioned at the exit site. Here, we determined the rpS26e oligopeptide neighboring mRNA on the human 80S ribosome using mRNA analogues bearing perfluorophenyl azide-derivatized nucleotides at designed locations. The protein was cross-linked to mRNA analogues in specific ribosomal complexes, in which the derivatized nucleotide was located at positions -3 to -9. Digestion of cross-linked rpS26e with various specific proteolytic agents followed by identification of the resulting modified oligopeptides made it possible to map the cross-links to fragment 60-71. This fragment contains the motif YxxPKxYxK conserved in eukaryotic but not in archaeal rpS26e. Analysis of X-ray structure of the Tetrahymena thermophila 40S subunit showed that this motif is not implicated in the intraribosomal interactions, implying its involvement in translation process in a eukaryote-specific manner. Comparison of the results obtained with data on positioning of ribosomal ligands on the 40S subunit lead us to suggest that this motif is involved in interaction with both the 5'-untranslated region of mRNA and the initiation factor eIF3 specific for eukaryotes, providing new insights into molecular mechanisms of translation in eukaryotes.
authors.affiliation: Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia.
authors.forename: Dmitri
authors.initials: D
authors.lastname: Sharifulin
authors.forename: Yulia
authors.initials: Y
authors.lastname: Khairulina
authors.forename: Anton
authors.initials: A
authors.lastname: Ivanov
authors.forename: Maria
authors.initials: M
authors.lastname: Meschaninova
authors.forename: Aliya
authors.initials: A
authors.lastname: Ven'yaminova
authors.forename: Dmitri
authors.initials: D
authors.lastname: Graifer
authors.forename: Galina
authors.initials: G
authors.lastname: Karpova
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001665:Binding Sites; D003062:Codon; D006801:Humans; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000737:chemistry*; D012269:Ribosomal Proteins / Q000737:chemistry*; D012270:Ribosomes / Q000737:chemistry; D017386:Sequence Homology, Amino Acid
chemical_list: D003062:Codon; D012333:RNA, Messenger; C489203:RPS26 protein, human; D012269:Ribosomal Proteins