Download MendeleyStructure-Based Mechanisms of a Molecular RNA Polymerase/Chaperone Machine Required for Ribosome Biosynthesis.
Huang, Y.H., Hilal, T., Loll, B., Burger, J., Mielke, T., Bottcher, C., Said, N., Wahl, M.C.(2020) Mol Cell 79: 1024-1036.e5
- PubMed: 32871103
- DOI: https://doi.org/10.1016/j.molcel.2020.08.010
- Primary Citation of Related Structures:
6TQN, 6TQO - PubMed Abstract:
Bacterial ribosomal RNAs are synthesized by a dedicated, conserved transcription-elongation complex that transcribes at high rates, shields RNA polymerase from premature termination, and supports co-transcriptional RNA folding, modification, processing, and ribosomal subunit assembly by presently unknown mechanisms. We have determined cryo-electron microscopy structures of complete Escherichia coli ribosomal RNA transcription elongation complexes, comprising RNA polymerase; DNA; RNA bearing an N-utilization-site-like anti-termination element; Nus factors A, B, E, and G; inositol mono-phosphatase SuhB; and ribosomal protein S4. Our structures and structure-informed functional analyses show that fast transcription and anti-termination involve suppression of NusA-stabilized pausing, enhancement of NusG-mediated anti-backtracking, sequestration of the NusG C-terminal domain from termination factor ρ, and the ρ blockade. Strikingly, the factors form a composite RNA chaperone around the RNA polymerase RNA-exit tunnel, which supports co-transcriptional RNA folding and annealing of distal RNA regions. Our work reveals a polymerase/chaperone machine required for biosynthesis of functional ribosomes.
Organizational Affiliation:
Laboratory of Structural Biochemistry, Institute of Chemistry and Biochemistry, Freie Universität Berlin, Takustraβe 6, 14195 Berlin, Germany.
