title: Molecular insights into the interaction of the ribosomal stalk protein with elongation factor 1α.
abstract: In all organisms, the large ribosomal subunit contains multiple copies of a flexible protein, the so-called 'stalk'. The C-terminal domain (CTD) of the stalk interacts directly with the translational GTPase factors, and this interaction is required for factor-dependent activity on the ribosome. Here we have determined the structure of a complex of the CTD of the archaeal stalk protein aP1 and the GDP-bound archaeal elongation factor aEF1α at 2.3 Å resolution. The structure showed that the CTD of aP1 formed a long extended α-helix, which bound to a cleft between domains 1 and 3 of aEF1α, and bridged these domains. This binding between the CTD of aP1 and the aEF1α•GDP complex was formed mainly by hydrophobic interactions. The docking analysis showed that the CTD of aP1 can bind to aEF1α•GDP located on the ribosome. An additional biochemical assay demonstrated that the CTD of aP1 also bound to the aEF1α•GTP•aminoacyl-tRNA complex. These results suggest that the CTD of aP1 interacts with aEF1α at various stages in translation. Furthermore, phylogenetic perspectives and functional analyses suggested that the eukaryotic stalk protein also interacts directly with domains 1 and 3 of eEF1α, in a manner similar to the interaction of archaeal aP1 with aEF1α.
authors.affiliation: Department of Biology, Faculty of Science, Niigata University, 8050 Ikarashi 2-no-cho, Nishi-ku, Niigata 950-2181, Japan uchiumi@bio.sc.niigata-u.ac.jp.
authors.forename: Kosuke
authors.initials: K
authors.lastname: Ito
authors.affiliation: Department of Biology, Faculty of Science, Niigata University, 8050 Ikarashi 2-no-cho, Nishi-ku, Niigata 950-2181, Japan.
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Honda
authors.affiliation: Department of Biology, Faculty of Science, Niigata University, 8050 Ikarashi 2-no-cho, Nishi-ku, Niigata 950-2181, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Suzuki
authors.affiliation: Department of Biology, Faculty of Science, Niigata University, 8050 Ikarashi 2-no-cho, Nishi-ku, Niigata 950-2181, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Miyoshi
authors.affiliation: Department of Biology, Faculty of Science, Niigata University, 8050 Ikarashi 2-no-cho, Nishi-ku, Niigata 950-2181, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Murakami
authors.affiliation: Faculty of Advanced Life Science, Hokkaido University, Kita-ku, Kita-10, Nishi-8, Sapporo 060-0810, Japan.
authors.forename: Min
authors.initials: M
authors.lastname: Yao
authors.affiliation: Department of Biology, Faculty of Science, Niigata University, 8050 Ikarashi 2-no-cho, Nishi-ku, Niigata 950-2181, Japan uchiumi@bio.sc.niigata-u.ac.jp.
authors.forename: Toshio
authors.initials: T
authors.lastname: Uchiumi
mesh_terms: D019943:Amino Acid Substitution; D019843:Archaeal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D008958:Models, Molecular; D020648:Peptide Elongation Factor 1 / Q000737:chemistry* / Q000378:metabolism; D010750:Phosphoproteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D043902:Pyrococcus horikoshii; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism; D012269:Ribosomal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D019843:Archaeal Proteins; D020648:Peptide Elongation Factor 1; D010750:Phosphoproteins; D012346:RNA, Transfer, Amino Acyl; D012269:Ribosomal Proteins; C035690:ribosomal phosphoprotein P1; D006160:Guanosine Triphosphate