ausblenden:
Schlagwörter:
Cryoelectron Microscopy; Crystallography, X-Ray; Escherichia coli/metabolism/ultrastructure; Eukaryotic Cells/metabolism/ultrastructure; Humans; Models, Molecular; Protein Biosynthesis; RNA, Ribosomal/ultrastructure; Ribosomes/chemistry/metabolism/ultrastructure; Saccharomyces cerevisiae/metabolism/ultrastructure; Triticum/metabolism/ultrastructure
Zusammenfassung:
Protein biosynthesis, the translation of the genetic code into polypeptides, occurs on ribonucleoprotein particles called ribosomes. Although X-ray structures of bacterial ribosomes are available, high-resolution structures of eukaryotic 80S ribosomes are lacking. Using cryoelectron microscopy and single-particle reconstruction, we have determined the structure of a translating plant (Triticum aestivum) 80S ribosome at 5.5-A resolution. This map, together with a 6.1-A map of a Saccharomyces cerevisiae 80S ribosome, has enabled us to model approximately 98% of the rRNA. Accurate assignment of the rRNA expansion segments (ES) and variable regions has revealed unique ES-ES and r-protein-ES interactions, providing insight into the structure and evolution of the eukaryotic ribosome.