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-Structure paper
Title | TraR allosterically regulates transcription initiation by altering RNA polymerase conformation. |
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Journal, issue, pages | Elife, Vol. 8, Year 2019 |
Publish date | Dec 16, 2019 |
Authors | James Chen / Saumya Gopalkrishnan / Courtney Chiu / Albert Y Chen / Elizabeth A Campbell / Richard L Gourse / Wilma Ross / Seth A Darst / |
PubMed Abstract | TraR and its homolog DksA are bacterial proteins that regulate transcription initiation by binding directly to RNA polymerase (RNAP) rather than to promoter DNA. Effects of TraR mimic the combined ...TraR and its homolog DksA are bacterial proteins that regulate transcription initiation by binding directly to RNA polymerase (RNAP) rather than to promoter DNA. Effects of TraR mimic the combined effects of DksA and its cofactor ppGpp, but the structural basis for regulation by these factors remains unclear. Here, we use cryo-electron microscopy to determine structures of RNAP, with or without TraR, and of an RNAP-promoter complex. TraR binding induced RNAP conformational changes not seen in previous crystallographic analyses, and a quantitative analysis revealed TraR-induced changes in RNAP conformational heterogeneity. These changes involve mobile regions of RNAP affecting promoter DNA interactions, including the βlobe, the clamp, the bridge helix, and several lineage-specific insertions. Using mutational approaches, we show that these structural changes, as well as effects on σ region 1.1, are critical for transcription activation or inhibition, depending on the kinetic features of regulated promoters. |
External links | Elife / PubMed:31841111 / PubMed Central |
Methods | EM (single particle) |
Resolution | 3.4 - 4.05 Å |
Structure data | EMDB-0348, PDB-6n57: EMDB-0349, PDB-6n58: EMDB-20203, PDB-6oul: EMDB-20230: Cryo-EM structure of Escherichia coli RNAP polymerase holoenzyme EMDB-20231: EMDB-20232: |
Chemicals | ChemComp-1N7: ChemComp-ZN: ChemComp-MG: |
Source |
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Keywords | TRANSFERASE / protein-DNA complex / transcription initiation / RNA polyermase / DNA promoter melting / Transcription |