title: Structure of the hypusinylated eukaryotic translation factor eIF-5A bound to the ribosome.
abstract: During protein synthesis, ribosomes become stalled on polyproline-containing sequences, unless they are rescued in archaea and eukaryotes by the initiation factor 5A (a/eIF-5A) and in bacteria by the homologous protein EF-P. While a structure of EF-P bound to the 70S ribosome exists, structural insight into eIF-5A on the 80S ribosome has been lacking. Here we present a cryo-electron microscopy reconstruction of eIF-5A bound to the yeast 80S ribosome at 3.9 Å resolution. The structure reveals that the unique and functionally essential post-translational hypusine modification reaches toward the peptidyltransferase center of the ribosome, where the hypusine moiety contacts A76 of the CCA-end of the P-site tRNA. These findings would support a model whereby eIF-5A stimulates peptide bond formation on polyproline-stalled ribosomes by stabilizing and orienting the CCA-end of the P-tRNA, rather than by directly contributing to the catalysis.
authors.affiliation: Gene Center, Department of Biochemistry and Center for integrated Protein Science Munich (CiPSM), Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377 Munich, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Schmidt
authors.affiliation: Gene Center, Department of Biochemistry and Center for integrated Protein Science Munich (CiPSM), Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377 Munich, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Becker
authors.affiliation: Gene Center, Department of Biochemistry and Center for integrated Protein Science Munich (CiPSM), Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377 Munich, Germany.
authors.forename: André
authors.initials: A
authors.lastname: Heuer
authors.affiliation: Gene Center, Department of Biochemistry and Center for integrated Protein Science Munich (CiPSM), Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377 Munich, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Braunger
authors.affiliation: Gene Center, Department of Biochemistry and Center for integrated Protein Science Munich (CiPSM), Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377 Munich, Germany.
authors.forename: Vivekanandan
authors.initials: V
authors.lastname: Shanmuganathan
authors.affiliation: Gene Center, Department of Biochemistry and Center for integrated Protein Science Munich (CiPSM), Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377 Munich, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Pech
authors.affiliation: Gene Center, Department of Biochemistry and Center for integrated Protein Science Munich (CiPSM), Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377 Munich, Germany.
authors.forename: Otto
authors.initials: O
authors.lastname: Berninghausen
authors.affiliation: Gene Center, Department of Biochemistry and Center for integrated Protein Science Munich (CiPSM), Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377 Munich, Germany wilson@genzentrum.lmu.de.
authors.forename: Daniel N
authors.initials: DN
authors.lastname: Wilson
authors.affiliation: Gene Center, Department of Biochemistry and Center for integrated Protein Science Munich (CiPSM), Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377 Munich, Germany beckmann@lmb.uni-muenchen.de.
authors.forename: Roland
authors.initials: R
authors.lastname: Beckmann
mesh_terms: D020285:Cryoelectron Microscopy; D010445:Peptide Elongation Factors / Q000737:chemistry / Q000378:metabolism; D010448:Peptide Initiation Factors / Q000737:chemistry* / Q000378:metabolism; D010455:Peptides / Q000235:genetics; D014176:Protein Biosynthesis / Q000235:genetics*; D011499:Protein Processing, Post-Translational / Q000235:genetics; D012333:RNA, Messenger / Q000737:chemistry / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D012270:Ribosomes / Q000737:chemistry* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000235:genetics; D000097574:Eukaryotic Translation Initiation Factor 5A
chemical_list: D010445:Peptide Elongation Factors; D010448:Peptide Initiation Factors; D010455:Peptides; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D000097574:Eukaryotic Translation Initiation Factor 5A; C020746:factor EF-P; C011083:polyproline