Snapshots of the Ribosomal Machinery by Cryo-Electron Mycroscopy

Abstract

Protein synthesis in all cells is performed by ribosomes, large protein-RNA complexes. Ribosomes undergo substantial conformational changes during their activity cycle and engage in interactions with numerous additional factors. In order to provide a mechanistic understanding of the underlying processes we aim at providing structural information on these complexes at highest possible resolution. We combine in vitro reconstitution and biochemical methods with cryo-electron microscopy and single particle analysis for structure determination. Furthermore complementary methods such as small angle X-ray scattering (SAXS), X-ray crystallography or Molecular Dynamics based simulations can be employed that often allow interpretations at the molecular level. Here we present snapshots of the ribosomal machinery engaged in several cotranslational events such as cotranslational protein folding, membrane translocation or insertion via the Sec complex.