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-Structure paper
Title | Structure-Based Mechanisms of a Molecular RNA Polymerase/Chaperone Machine Required for Ribosome Biosynthesis. |
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Journal, issue, pages | Mol Cell, Vol. 79, Issue 6, Page 1024-11036.e5, Year 2020 |
Publish date | Sep 17, 2020 |
Authors | Yong-Heng Huang / Tarek Hilal / Bernhard Loll / Jörg Bürger / Thorsten Mielke / Christoph Böttcher / Nelly Said / Markus C Wahl / |
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- ...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. |
External links | Mol Cell / PubMed:32871103 |
Methods | EM (single particle) |
Resolution | 3.6 - 4.0 Å |
Structure data | EMDB-10545: EMDB-10546: bacterial RNA polymerase rrnTAC delta S4 (state 1) EMDB-10547: EMDB-10548: bacterial RNA polymerase rrnTAC (state1) |
Chemicals | ChemComp-MG: ChemComp-ZN: |
Source |
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Keywords | TRANSCRIPTION / rrn / anti-termination complex / RNAP / Nus factors / SuhB / S4 |