EMD-10546

Single-particle
3.8 Å
EMD-10546 Deposition: 16/12/2019
Map released: 16/12/2020
Last modified: 14/04/2021
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links

EMD-10546

bacterial RNA polymerase rrnTAC delta S4 (state 1)

EMD-10546

Single-particle
3.8 Å
EMD-10546 Deposition: 16/12/2019
Map released: 16/12/2020
Last modified: 14/04/2021
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Sample Organism: Escherichia coli
Sample: bacterial rRNA transcription anti-termination complex

Deposition Authors: Hilal T, Huang Y, Wahl MC
Structure-Based Mechanisms of a Molecular RNA Polymerase/Chaperone Machine Required for Ribosome Biosynthesis.
Huang YH, Hilal T , Loll B , Burger J , Mielke T, Bottcher C, Said N, Wahl MC
(2020) Mol. Cell , 79 , 1024 - 1036.e5
PUBMED: 32871103
DOI: doi:10.1016/j.molcel.2020.08.010
ISSN: 1097-2765
ASTM: MOCEFL
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.