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- EMDB-48580: de novo SigN RNA polymerase transcription initiation intermediate... -
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Open data
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Basic information
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Title | de novo SigN RNA polymerase transcription initiation intermediate with pre-catalytic bEBP state (RPi1 open ring), consensus map | |||||||||
![]() | unsharpened consensus map | |||||||||
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![]() | sigma N / sigma 54 / ATPase / bacterial enhancer binding protein / transcription initiation / intermediate / TRANSCRIPTION | |||||||||
Biological species | ![]() ![]() | |||||||||
Method | single particle reconstruction / cryo EM / Resolution: 2.7 Å | |||||||||
![]() | Mueller AU / Darst SA | |||||||||
Funding support | ![]()
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![]() | ![]() Title: Real-time capture of σ transcription initiation intermediates reveals mechanism of ATPase-driven activation by limited unfolding. Authors: Andreas U Mueller / Nina Molina / B Tracy Nixon / Seth A Darst / ![]() Abstract: Bacterial σ factors bind RNA polymerase (E) to form holoenzyme (Eσ), conferring promoter specificity to E and playing a key role in transcription bubble formation. σ is unique among σ factors in ...Bacterial σ factors bind RNA polymerase (E) to form holoenzyme (Eσ), conferring promoter specificity to E and playing a key role in transcription bubble formation. σ is unique among σ factors in its structure and functional mechanism, requiring activation by specialized AAA+ ATPases. Eσ forms an inactive promoter complex where the N-terminal σ region I (σ-RI) threads through a small DNA bubble. On the opposite side of the DNA, the ATPase engages σ-RI within the pore of its hexameric ring. Here, we perform kinetics-guided structural analysis of de novo formed Eσ initiation complexes and engineer a biochemical assay to measure ATPase-mediated σ-RI translocation during promoter melting. We show that the ATPase exerts mechanical action to translocate about 30 residues of σ-RI through the DNA bubble, disrupting inhibitory structures of σ to allow full transcription bubble formation. A local charge switch of σ-RI from positive to negative may help facilitate disengagement of the otherwise processive ATPase, allowing subsequent σ disentanglement from the DNA bubble. | |||||||||
History |
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Structure visualization
Supplemental images |
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Downloads & links
-EMDB archive
Map data | ![]() | 172.1 MB | ![]() | |
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Header (meta data) | ![]() ![]() | 17.7 KB 17.7 KB | Display Display | ![]() |
FSC (resolution estimation) | ![]() | 14.8 KB | Display | ![]() |
Images | ![]() | 109 KB | ||
Filedesc metadata | ![]() | 4.6 KB | ||
Others | ![]() ![]() ![]() | 324.2 MB 318.1 MB 318.1 MB | ||
Archive directory | ![]() ![]() | HTTPS FTP |
-Validation report
Summary document | ![]() | 971.5 KB | Display | ![]() |
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Full document | ![]() | 971.1 KB | Display | |
Data in XML | ![]() | 24.2 KB | Display | |
Data in CIF | ![]() | 31.5 KB | Display | |
Arichive directory | ![]() ![]() | HTTPS FTP |
-Related structure data
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Links
EMDB pages | ![]() ![]() |
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Map
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Annotation | unsharpened consensus map | ||||||||||||||||||||||||||||||||||||
Projections & slices | Image control
Images are generated by Spider. | ||||||||||||||||||||||||||||||||||||
Voxel size | X=Y=Z: 0.86 Å | ||||||||||||||||||||||||||||||||||||
Density |
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Symmetry | Space group: 1 | ||||||||||||||||||||||||||||||||||||
Details | EMDB XML:
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-Supplemental data
-Additional map: sharpened consensus map (b-factor 61.6)
File | emd_48580_additional_1.map | ||||||||||||
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Annotation | sharpened consensus map (b-factor 61.6) | ||||||||||||
Projections & Slices |
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Density Histograms |
-Half map: half map B
File | emd_48580_half_map_1.map | ||||||||||||
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Annotation | half map B | ||||||||||||
Projections & Slices |
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Density Histograms |
-Half map: half map A
File | emd_48580_half_map_2.map | ||||||||||||
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Annotation | half map A | ||||||||||||
Projections & Slices |
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Density Histograms |
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Sample components
-Entire : EsNdhsUC1+ATP
Entire | Name: EsNdhsUC1+ATP |
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Components |
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-Supramolecule #1: EsNdhsUC1+ATP
Supramolecule | Name: EsNdhsUC1+ATP / type: complex / ID: 1 / Parent: 0 / Macromolecule list: #1-#8 Details: E = RNAP sN = Sigma N dhsU = dhsU promoter DNA C1 = NtrC1 |
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Source (natural) | Organism: ![]() ![]() |
Molecular weight | Theoretical: 180 KDa |
-Experimental details
-Structure determination
Method | cryo EM |
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![]() | single particle reconstruction |
Aggregation state | particle |
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Sample preparation
Buffer | pH: 8 Details: 40 mM Tris-HCl, pH 8/RT, 200 mM KCl, 10 mM MgCl2, 1 mM DTT; fluorinated fos-choline-8 (FC8F) added to a final concentration of 1.5 mM during grid preparation |
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Grid | Model: C-flat-1.2/1.3 / Material: GOLD / Mesh: 400 / Support film - Material: CARBON / Support film - topology: HOLEY |
Vitrification | Cryogen name: ETHANE / Chamber humidity: 100 % / Chamber temperature: 310 K / Instrument: FEI VITROBOT MARK IV |
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Electron microscopy
Microscope | TFS KRIOS |
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Image recording | Film or detector model: GATAN K3 BIOQUANTUM (6k x 4k) / Digitization - Dimensions - Width: 11520 pixel / Digitization - Dimensions - Height: 8184 pixel / Number grids imaged: 1 / Number real images: 17199 / Average exposure time: 1.4 sec. / Average electron dose: 42.0 e/Å2 |
Electron beam | Acceleration voltage: 300 kV / Electron source: ![]() |
Electron optics | Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD / Nominal defocus max: 2.2 µm / Nominal defocus min: 0.8 µm |
Sample stage | Cooling holder cryogen: NITROGEN |
Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |