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Yorodumi- PDB-9ex7: Cryo-EM structure of the E. coli BrxX methyltransferase in comple... -
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Open data
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Basic information
| Entry | Database: PDB / ID: 9ex7 | |||||||||||||||
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| Title | Cryo-EM structure of the E. coli BrxX methyltransferase in complex with Ocr | |||||||||||||||
Components |
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Keywords | TRANSFERASE / Methyltransferase / phage defense / BREX / DNA-binding | |||||||||||||||
| Function / homology | Function and homology informationsymbiont-mediated evasion of host restriction-modification system / DNA modification / site-specific DNA-methyltransferase (adenine-specific) / site-specific DNA-methyltransferase (adenine-specific) activity / methylation / defense response to virus / nucleic acid binding / symbiont-mediated suppression of host innate immune response Similarity search - Function | |||||||||||||||
| Biological species | ![]() ![]() Escherichia phage T7 (virus) | |||||||||||||||
| Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 2.91 Å | |||||||||||||||
Authors | Adams, M.C. / Ghilarov, D. | |||||||||||||||
| Funding support | United Kingdom, 2items
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Citation | Journal: Nat Commun / Year: 2025Title: Molecular basis of foreign DNA recognition by BREX anti-phage immunity system. Authors: Alena Drobiazko / Myfanwy C Adams / Mikhail Skutel / Kristina Potekhina / Oksana Kotovskaya / Anna Trofimova / Mikhail Matlashov / Daria Yatselenko / Karen L Maxwell / Tim R Blower / ...Authors: Alena Drobiazko / Myfanwy C Adams / Mikhail Skutel / Kristina Potekhina / Oksana Kotovskaya / Anna Trofimova / Mikhail Matlashov / Daria Yatselenko / Karen L Maxwell / Tim R Blower / Konstantin Severinov / Dmitry Ghilarov / Artem Isaev / ![]() Abstract: Anti-phage systems of the BREX (BacteRiophage EXclusion) superfamily rely on site-specific epigenetic DNA methylation to discriminate between the host and invading DNA. We demonstrate that in Type I ...Anti-phage systems of the BREX (BacteRiophage EXclusion) superfamily rely on site-specific epigenetic DNA methylation to discriminate between the host and invading DNA. We demonstrate that in Type I BREX systems, defense and methylation require BREX site DNA binding by the BrxX (PglX) methyltransferase employing S-adenosyl methionine as a cofactor. We determined 2.2-Å cryoEM structure of Escherichia coli BrxX bound to target dsDNA revealing molecular details of BREX DNA recognition. Structure-guided engineering of BrxX expands its DNA specificity and dramatically enhances phage defense. We show that BrxX alone does not methylate DNA, and BREX activity requires an assembly of a supramolecular BrxBCXZ immune complex. Finally, we present a cryoEM structure of BrxX bound to a phage-encoded inhibitor Ocr that sequesters BrxX in an inactive dimeric form. We propose that BrxX-mediated foreign DNA sensing is a necessary first step in activation of BREX defense. | |||||||||||||||
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Structure visualization
| Structure viewer | Molecule: Molmil Jmol/JSmol |
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Downloads & links
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Download
| PDBx/mmCIF format | 9ex7.cif.gz | 523 KB | Display | PDBx/mmCIF format |
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| PDB format | pdb9ex7.ent.gz | 421.7 KB | Display | PDB format |
| PDBx/mmJSON format | 9ex7.json.gz | Tree view | PDBx/mmJSON format | |
| Others | Other downloads |
-Validation report
| Summary document | 9ex7_validation.pdf.gz | 914.7 KB | Display | wwPDB validaton report |
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| Full document | 9ex7_full_validation.pdf.gz | 932.6 KB | Display | |
| Data in XML | 9ex7_validation.xml.gz | 66.2 KB | Display | |
| Data in CIF | 9ex7_validation.cif.gz | 103.4 KB | Display | |
| Arichive directory | https://data.pdbj.org/pub/pdb/validation_reports/ex/9ex7 ftp://data.pdbj.org/pub/pdb/validation_reports/ex/9ex7 | HTTPS FTP |
-Related structure data
| Related structure data | ![]() 50032MC ![]() 9ewzC ![]() 9exhC C: citing same article ( M: map data used to model this data |
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| Similar structure data | Similarity search - Function & homology F&H Search |
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Links
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Assembly
| Deposited unit | ![]()
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Components
| #1: Protein | Mass: 138128.328 Da / Num. of mol.: 2 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() References: UniProt: P0DUF9, site-specific DNA-methyltransferase (adenine-specific) #2: Protein | Mass: 13819.015 Da / Num. of mol.: 2 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() Escherichia phage T7 (virus) / Gene: 0.3 / Production host: ![]() #3: Chemical | #4: Chemical | ChemComp-SAM / | Has ligand of interest | Y | Has protein modification | N | |
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-Experimental details
-Experiment
| Experiment | Method: ELECTRON MICROSCOPY |
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| EM experiment | Aggregation state: 2D ARRAY / 3D reconstruction method: single particle reconstruction |
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Sample preparation
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| Buffer solution | pH: 7.5 | ||||||||||||||||||||||||
| Specimen | Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES | ||||||||||||||||||||||||
| Vitrification | Cryogen name: ETHANE |
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Electron microscopy imaging
| Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |
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| Microscopy | Model: TFS KRIOS |
| Electron gun | Electron source: FIELD EMISSION GUN / Accelerating voltage: 300 kV / Illumination mode: FLOOD BEAM |
| Electron lens | Mode: BRIGHT FIELD / Nominal defocus max: 3000 nm / Nominal defocus min: 900 nm |
| Image recording | Electron dose: 35.1 e/Å2 / Film or detector model: FEI FALCON IV (4k x 4k) |
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Processing
| EM software | Name: PHENIX / Category: model refinement | ||||||||||||||||||||||||
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| CTF correction | Type: PHASE FLIPPING AND AMPLITUDE CORRECTION | ||||||||||||||||||||||||
| 3D reconstruction | Resolution: 2.91 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 94764 / Symmetry type: POINT | ||||||||||||||||||||||||
| Refine LS restraints |
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Escherichia phage T7 (virus)
United Kingdom, 2items
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FIELD EMISSION GUN