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PDBsum entry 7khc
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Transcription/DNA
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PDB id
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7khc
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Contents |
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309 a.a.
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1340 a.a.
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1342 a.a.
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76 a.a.
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447 a.a.
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References listed in PDB file
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Key reference
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Title
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Structural basis of ribosomal RNA transcription regulation.
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Authors
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Y.Shin,
M.Z.Qayyum,
D.Pupov,
D.Esyunina,
A.Kulbachinskiy,
K.S.Murakami.
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Ref.
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Nat Commun, 2021,
12,
528.
[DOI no: ]
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PubMed id
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Abstract
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Ribosomal RNA (rRNA) is most highly expressed in rapidly growing bacteria and is
drastically downregulated under stress conditions by the global transcriptional
regulator DksA and the alarmone ppGpp. Here, we determined cryo-electron
microscopy structures of the Escherichia coli RNA polymerase (RNAP)
σ70 holoenzyme during rRNA promoter recognition with and without
DksA/ppGpp. RNAP contacts the UP element using dimerized α subunit
carboxyl-terminal domains and scrunches the template DNA with the σ finger and
β' lid to select the transcription start site favorable for rapid
promoter escape. Promoter binding induces conformational change of σ domain 2
that opens a gate for DNA loading and ejects σ1.1 from the RNAP
cleft to facilitate open complex formation. DksA/ppGpp binding also opens the
DNA loading gate, which is not coupled to σ1.1 ejection and impedes
open complex formation. These results provide a molecular basis for the
exceptionally active rRNA transcription and its vulnerability to DksA/ppGpp.
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