title: LOOP IIId of the HCV IRES is essential for the structural rearrangement of the 40S-HCV IRES complex.
abstract: As obligatory intracellular parasites, viruses rely on cellular machines to complete their life cycle, and most importantly they recruit the host ribosomes to translate their mRNA. The Hepatitis C viral mRNA initiates translation by directly binding the 40S ribosomal subunit in such a way that the initiation codon is correctly positioned in the P site of the ribosome. Such a property is likely to be central for many viruses, therefore the description of host-pathogen interaction at the molecular level is instrumental to provide new therapeutic targets. In this study, we monitored the 40S ribosomal subunit and the viral RNA structural rearrangement induced upon the formation of the binary complex. We further took advantage of an IRES viral mutant mRNA deficient for translation to identify the interactions necessary to promote translation. Using a combination of structure probing in solution and molecular modeling we establish a whole atom model which appears to be very similar to the one obtained recently by cryoEM. Our model brings new information on the complex, and most importantly reveals some structural rearrangement within the ribosome. This study suggests that the formation of a 'kissing complex' between the viral RNA and the 18S ribosomal RNA locks the 40S ribosomal subunit in a conformation proficient for translation.
authors.affiliation: CNRS UMR 8015, Laboratoire de cristallographie et RMN Biologiques, Université Paris Descartes, 4 avenue de l'Observatoire, 75270 Paris Cedex 06, France Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile.
authors.forename: Jenniffer
authors.initials: J
authors.lastname: Angulo
authors.affiliation: CNRS UMR 8015, Laboratoire de cristallographie et RMN Biologiques, Université Paris Descartes, 4 avenue de l'Observatoire, 75270 Paris Cedex 06, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Ulryck
authors.affiliation: CNRS UMR 8015, Laboratoire de cristallographie et RMN Biologiques, Université Paris Descartes, 4 avenue de l'Observatoire, 75270 Paris Cedex 06, France.
authors.forename: Jules
authors.initials: J
authors.lastname: Deforges
authors.affiliation: CNRS UMR 8015, Laboratoire de cristallographie et RMN Biologiques, Université Paris Descartes, 4 avenue de l'Observatoire, 75270 Paris Cedex 06, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Chamond
authors.affiliation: Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Lopez-Lastra
authors.affiliation: UMR 7156 Génétique Moléculaire Génomique Microbiologie, CNRS - Université de Strasbourg, Strasbourg, France b.masquida@unistra.fr.
authors.forename: Benoît
authors.initials: B
authors.lastname: Masquida
authors.affiliation: CNRS UMR 8015, Laboratoire de cristallographie et RMN Biologiques, Université Paris Descartes, 4 avenue de l'Observatoire, 75270 Paris Cedex 06, France bruno.sargueil@parisdescartes.fr.
authors.forename: Bruno
authors.initials: B
authors.lastname: Sargueil
mesh_terms: D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002474:Cell-Free System; D018387:Codon, Initiator / Q000235:genetics; D020285:Cryoelectron Microscopy; D006367:HeLa Cells; D016174:Hepacivirus / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D054884:Host-Pathogen Interactions; D006801:Humans; D000067556:Internal Ribosome Entry Sites / Q000235:genetics*; D046911:Macromolecular Substances / Q000378:metabolism / Q000648:ultrastructure; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D009690:Nucleic Acid Conformation; D010442:Peptide Chain Initiation, Translational / Q000235:genetics; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012337:RNA, Ribosomal, 18S / Q000235:genetics / Q000378:metabolism; D012367:RNA, Viral / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D011817:Rabbits; D054682:Ribosome Subunits, Small, Eukaryotic / Q000235:genetics* / Q000378:metabolism
chemical_list: D018387:Codon, Initiator; D000067556:Internal Ribosome Entry Sites; D046911:Macromolecular Substances; D012333:RNA, Messenger; D012337:RNA, Ribosomal, 18S; D012367:RNA, Viral