The molecular structure of the left-handed supra-molecular helix of eukaryotic polyribosomes.Myasnikov, A.G., Afonina, Z.A., Menetret, J.F., Shirokov, V.A., Spirin, A.S., Klaholz, B.P.
(2014) Nat Commun 5: 5294-5294
- PubMed: 25376914
- DOI: 10.1038/ncomms6294
- PubMed Abstract:
During protein synthesis, several ribosomes bind to a single messenger RNA (mRNA) forming large macromolecular assemblies called polyribosomes. Here we report the detailed molecular structure of a 100 MDa eukaryotic poly-ribosome complex derived from ...
During protein synthesis, several ribosomes bind to a single messenger RNA (mRNA) forming large macromolecular assemblies called polyribosomes. Here we report the detailed molecular structure of a 100 MDa eukaryotic poly-ribosome complex derived from cryo electron tomography, sub-tomogram averaging and pseudo-atomic modelling by crystal structure fitting. The structure allowed the visualization of the three functional parts of the polysome assembly, the central core region that forms a rather compact left-handed supra-molecular helix, and the more open regions that harbour the initiation and termination sites at either ends. The helical region forms a continuous mRNA channel where the mRNA strand bridges neighbouring exit and entry sites of the ribosomes and prevents mRNA looping between ribosomes. This structure provides unprecedented insights into protein- and RNA-mediated inter-ribosome contacts that involve conserved sites through 40S subunits and long protruding RNA expansion segments, suggesting a role in stabilizing the overall polyribosomal assembly.
1] Centre for Integrative Biology (CBI), Department of Integrated Structural Biology, IGBMC (Institute of Genetics and of Molecular and Cellular Biology), 1 rue Laurent Fries, BP 10142, 67404 Illkirch, France  Centre National de la Recherche Scientifique (CNRS) UMR 7104, 67404 Illkirch, France  Institut National de la Santé et de la Recherche Médicale (INSERM), 67404 Illkirch, France  Université de Strasbourg, 67400 Strasbourg, France.