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Yorodumi- EMDB-18661: Structure of the Bacteriophage PhiKZ non-virion RNA Polymerase bo... -
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Open data
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Basic information
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| Title | Structure of the Bacteriophage PhiKZ non-virion RNA Polymerase bound to DNA and RNA | |||||||||
Map data | PhiKZ nvRNAP DNA/RNA complex Postprocessed Map | |||||||||
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Keywords | PhiKZ / nvRNAP / RNA / DNA / transcription / RNA BINDING PROTEIN | |||||||||
| Function / homology | PHIKZ123 / PHIKZ074 / PHIKZ068 / PHIKZ055 Function and homology information | |||||||||
| Biological species | Pseudomonas phage phiKZ (virus) | |||||||||
| Method | single particle reconstruction / cryo EM / Resolution: 3.3 Å | |||||||||
Authors | de Martin Garrido N / Yakunina M / Aylett CHS | |||||||||
| Funding support | United Kingdom, 2 items
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Citation | Journal: IUCrJ / Year: 2026Title: Structure of the bacteriophage PhiKZ non-virion RNA polymerase bound to a p119L open promoter analogue. Authors: Chao Sheng Chen / Natàlia de Martín Garrido / Maria Yakunina / Christopher H S Aylett / ![]() Abstract: Bacteriophage ΦKZ (PhiKZ) was the first identified member of a family of massive bacterial viruses. ΦKZ infects Pseudomonas aeruginosa, which kills tens of thousands every year, and it therefore ...Bacteriophage ΦKZ (PhiKZ) was the first identified member of a family of massive bacterial viruses. ΦKZ infects Pseudomonas aeruginosa, which kills tens of thousands every year, and it therefore has potential as a bacteriophage therapy. On infection, ΦKZ forms a `nucleus' to protect its genome by excluding host immune systems. This barrier means that it has had to become independent of the host transcriptional apparatus; it cannot simply recruit the host RNA polymerase (RNAP) to its promoters as it is excluded from the viral DNA, and therefore it expresses and imports its own non-virion RNA polymerase (nvRNAP). The ΦKZ nvRNAP, and related jumbo-phage RNAPs including that from bacteriophage AR9, are particularly noteworthy. Unlike typical viral RNAPs which are formed as only a single subunit, it is a non-canonical multi-subunit RNAP directly related to those from eubacteria, and more distantly eukaryotes and archaea. It encompasses four proteins representing patchwork homologues of the eubacterial β/β' subunits, and a fifth that appears to have evolved from a σ factor, but no homologues of the α or ω subunits required for formation of a catalytically active complex in eubacterial RNAPs. Its mechanism of promoter recognition is also highly divergent; transcription is initiated from a site marked only by a tiny four-base consensus sequence co-located with the start site. We have resolved the structure of the ΦKZ nvRNAP bound to an open analogue of its cognate promoter, p119L, revealing that while the σ-factor-like subunit GP68 is involved in bubble stabilization, the sequence-specific promoter consensus sequence is bound between the lobe of the β-subunit homologue GP123 and the enzymatic core of the complex. Our results shed light on the differences between mechanisms of promoter recognition in the ΦKZ nvRNAP and canonical eubacterial RNAPs, and on the uniquely specialized features of bacteriophage transcriptional apparatuses in general. | |||||||||
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Structure visualization
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Downloads & links
-EMDB archive
| Map data | emd_18661.map.gz | 59.1 MB | EMDB map data format | |
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| Header (meta data) | emd-18661-v30.xml emd-18661.xml | 39.3 KB 39.3 KB | Display Display | EMDB header |
| FSC (resolution estimation) | emd_18661_fsc.xml | 9.1 KB | Display | FSC data file |
| Images | emd_18661.png | 199.9 KB | ||
| Filedesc metadata | emd-18661.cif.gz | 10.3 KB | ||
| Others | emd_18661_additional_1.map.gz emd_18661_half_map_1.map.gz emd_18661_half_map_2.map.gz | 445.8 MB 49.6 MB 49.6 MB | ||
| Archive directory | http://ftp.pdbj.org/pub/emdb/structures/EMD-18661 ftp://ftp.pdbj.org/pub/emdb/structures/EMD-18661 | HTTPS FTP |
-Related structure data
| Related structure data | ![]() 8queMC M: atomic model generated by this map C: citing same article ( |
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| Similar structure data | Similarity search - Function & homology F&H Search |
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Links
| EMDB pages | EMDB (EBI/PDBe) / EMDataResource |
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Map
| File | Download / File: emd_18661.map.gz / Format: CCP4 / Size: 64 MB / Type: IMAGE STORED AS FLOATING POINT NUMBER (4 BYTES) | ||||||||||||||||||||||||||||||||||||
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| Annotation | PhiKZ nvRNAP DNA/RNA complex Postprocessed Map | ||||||||||||||||||||||||||||||||||||
| Projections & slices | Image control
Images are generated by Spider. | ||||||||||||||||||||||||||||||||||||
| Voxel size | X=Y=Z: 0.92 Å | ||||||||||||||||||||||||||||||||||||
| Density |
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| Symmetry | Space group: 1 | ||||||||||||||||||||||||||||||||||||
| Details | EMDB XML:
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-Supplemental data
-Additional map: PhiKZ nvRNAP DNA/RNA complex Locally Filtered Map
| File | emd_18661_additional_1.map | ||||||||||||
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| Annotation | PhiKZ nvRNAP DNA/RNA complex Locally Filtered Map | ||||||||||||
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| Density Histograms |
-Half map: PhiKZ nvRNAP DNA/RNA complex Half Map 1
| File | emd_18661_half_map_1.map | ||||||||||||
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| Annotation | PhiKZ nvRNAP DNA/RNA complex Half Map 1 | ||||||||||||
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| Density Histograms |
-Half map: PhiKZ nvRNAP DNA/RNA complex Half Map 2
| File | emd_18661_half_map_2.map | ||||||||||||
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| Annotation | PhiKZ nvRNAP DNA/RNA complex Half Map 2 | ||||||||||||
| Projections & Slices |
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| Density Histograms |
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Sample components
+Entire : PhiKZ non-virion RNA polymerase transcribing promoter P119L
+Supramolecule #1: PhiKZ non-virion RNA polymerase transcribing promoter P119L
+Macromolecule #1: PHIKZ055
+Macromolecule #2: DNA-directed RNA polymerase
+Macromolecule #3: PHIKZ074
+Macromolecule #4: PHIKZ123
+Macromolecule #8: PHIKZ068
+Macromolecule #5: DNA
+Macromolecule #6: DNA
+Macromolecule #9: DNA
+Macromolecule #7: RNA
+Macromolecule #10: ZINC ION
-Experimental details
-Structure determination
| Method | cryo EM |
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Processing | single particle reconstruction |
| Aggregation state | particle |
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Sample preparation
| Concentration | 0.1 mg/mL | ||||||||
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| Buffer | pH: 8 Component:
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| Grid | Model: Quantifoil R2/1 / Material: COPPER / Mesh: 300 / Support film - Material: GRAPHENE OXIDE / Support film - topology: CONTINUOUS / Pretreatment - Type: PLASMA CLEANING / Pretreatment - Time: 15 sec. / Pretreatment - Atmosphere: AIR | ||||||||
| Vitrification | Cryogen name: ETHANE / Chamber humidity: 100 % / Chamber temperature: 278 K / Instrument: FEI VITROBOT MARK IV Details: Settings: -6 blot force, 4 s waiting time and 0.5-1 s blotting time.. | ||||||||
| Details | PhiKZ nvRNAP complexes were mixed at 0.1 mg/mL final concentration with the P119L DNA/RNA template at a 1:1 ratio in the presence of 1 mM ATP, CTP and GTP. Reactions were incubated for 30 min at 37 C before use. |
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Electron microscopy
| Microscope | FEI TITAN KRIOS |
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| Specialist optics | Energy filter - Name: TFS Selectris X / Energy filter - Slit width: 10 eV |
| Image recording | Film or detector model: FEI FALCON IV (4k x 4k) / Digitization - Dimensions - Width: 4096 pixel / Digitization - Dimensions - Height: 4096 pixel / Number grids imaged: 1 / Number real images: 3092 / Average electron dose: 51.0 e/Å2 |
| Electron beam | Acceleration voltage: 300 kV / Electron source: FIELD EMISSION GUN |
| Electron optics | C2 aperture diameter: 50.0 µm / Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD / Cs: 2.7 mm / Nominal defocus max: 2.9 µm / Nominal defocus min: 1.4000000000000001 µm / Nominal magnification: 15000 |
| Sample stage | Specimen holder model: FEI TITAN KRIOS AUTOGRID HOLDER / Cooling holder cryogen: NITROGEN |
| Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |
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Image processing
-Atomic model buiding 1
| Initial model |
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| Refinement | Space: REAL / Protocol: AB INITIO MODEL / Target criteria: CC | |||||||||||||||
| Output model | ![]() PDB-8que: |
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About Yorodumi



Keywords
Pseudomonas phage phiKZ (virus)
Authors
United Kingdom, 2 items
Citation



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FIELD EMISSION GUN



