Funding Organization(s): European Research Council (ERC), French Infrastructure for Integrated Structural Biology (FRISBI), French National Research Agency, European Molecular Biology Organization (EMBO)
Prokaryotic messenger RNAs (mRNAs) are translated as they are transcribed. The lead ribosome potentially contacts RNA polymerase (RNAP) and forms a supramolecular complex known as the expressome. The basis of expressome assembly and its consequences for transcription and translation are poorly understood. Here, we present a series of structures representing uncoupled, coupled, and collided expressome states determined by cryo-electron microscopy. A bridge between the ribosome and RNAP can be formed by the transcription factor NusG, which stabilizes an otherwise-variable interaction interface. Shortening of the intervening mRNA causes a substantial rearrangement that aligns the ribosome entrance channel to the RNAP exit channel. In this collided complex, NusG linkage is no longer possible. These structures reveal mechanisms of coordination between transcription and translation and provide a framework for future study.
Organizational Affiliation:
Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67404 Illkirch, France.
Université de Strasbourg, 67404 Illkirch, France.
CNRS UMR7104, 67404 Illkirch, France.
INSERM U1258, 67404 Illkirch, France.
Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67404 Illkirch, France. albert.weixlbaumer@igbmc.fr.
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