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Open data
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Basic information
| Entry | Database: PDB / ID: 9vdp | ||||||||||||||||||||||||
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| Title | Cryo-EM structure of the hexameric DRT4 | ||||||||||||||||||||||||
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Keywords | DNA BINDING PROTEIN/DNA / UG15 / DRT4 / Reverse transcriptases / UG/Abi system / DNA BINDING PROTEIN-DNA complex | ||||||||||||||||||||||||
| Function / homology | Reverse transcriptase domain / Reverse transcriptase (RNA-dependent DNA polymerase) / Reverse transcriptase (RT) catalytic domain profile. / DNA / Reverse transcriptase domain-containing protein Function and homology information | ||||||||||||||||||||||||
| Biological species | ![]() | ||||||||||||||||||||||||
| Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 2.27 Å | ||||||||||||||||||||||||
Authors | Wang, Y. / Deng, Z. | ||||||||||||||||||||||||
| Funding support | 1items
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Citation | Journal: Nat Commun / Year: 2025Title: Anti-phage defense mechanism involving phage-encoded DNA binding protein and bacterial reverse transcriptase DRT4. Authors: Yong Wang / Hao Wu / Jinyue Li / Qiyin An / Zhenhua Tian / Zengqin Deng / ![]() Abstract: Prokaryotic defense-associated reverse transcriptase (DRT) systems confer host resistance to viral infection through DNA synthesis; however, the molecular mechanisms underlying their function remain ...Prokaryotic defense-associated reverse transcriptase (DRT) systems confer host resistance to viral infection through DNA synthesis; however, the molecular mechanisms underlying their function remain poorly understood. Here, we demonstrate that DRT4, a single-gene anti-phage defense system, synthesizes single-stranded DNA (ssDNA) products of random sequences in a template-independent manner. High-resolution cryo-EM structures of DRT4 in multiple functional states elucidate its oligomeric architecture, catalytic metal ion coordination, and substrate/DNA product binding, offering mechanistic insights into its promiscuous polymerization activity. Structural and biochemical analyses further identify a conserved tyrosine residue that acts as the priming site for the initiation of DNA synthesis. Upon phage infection, a phage-encoded DNA-binding protein, ORF55, protects the 3' end of the DRT4-synthesized ssDNA from host exonuclease degradation, likely resulting in toxic ssDNA accumulation that leads to cell death. Remarkably, ORF55 also activates DRT6, a structural homolog of DRT4, suggesting a conserved activation mechanism among related DRT systems. These findings provide structural and mechanistic insights into DRT4-mediated antiviral defense, establishing a distinct paradigm for antiviral reverse transcriptase in bacterial immunity. | ||||||||||||||||||||||||
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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 | 9vdp.cif.gz | 596.3 KB | Display | PDBx/mmCIF format |
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| PDB format | pdb9vdp.ent.gz | 492.5 KB | Display | PDB format |
| PDBx/mmJSON format | 9vdp.json.gz | Tree view | PDBx/mmJSON format | |
| Others | Other downloads |
-Validation report
| Arichive directory | https://data.pdbj.org/pub/pdb/validation_reports/vd/9vdp ftp://data.pdbj.org/pub/pdb/validation_reports/vd/9vdp | HTTPS FTP |
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-Related structure data
| Related structure data | ![]() 64991MC ![]() 9vdoC ![]() 9vdvC M: map data used to model this data C: citing same article ( |
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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: 63911.047 Da / Num. of mol.: 6 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() #2: DNA chain | Mass: 1449.002 Da / Num. of mol.: 6 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() Has protein modification | N | |
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-Experimental details
-Experiment
| Experiment | Method: ELECTRON MICROSCOPY |
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| EM experiment | Aggregation state: PARTICLE / 3D reconstruction method: single particle reconstruction |
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Sample preparation
| Component | Name: DRT4-DNA / Type: COMPLEX / Entity ID: all / Source: RECOMBINANT |
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| Source (natural) | Organism: ![]() |
| Source (recombinant) | Organism: ![]() |
| Buffer solution | pH: 8 |
| Specimen | Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES |
| Vitrification | Cryogen name: ETHANE |
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Electron microscopy imaging
| Microscopy | Model: JEOL CRYO ARM 300 |
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| Electron gun | Electron source: FIELD EMISSION GUN / Accelerating voltage: 300 kV / Illumination mode: FLOOD BEAM |
| Electron lens | Mode: BRIGHT FIELD / Nominal defocus max: 2500 nm / Nominal defocus min: 500 nm |
| Image recording | Electron dose: 40 e/Å2 / Film or detector model: GATAN K3 (6k x 4k) |
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Processing
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| CTF correction | Type: PHASE FLIPPING ONLY | ||||||||||||||||||||||||
| 3D reconstruction | Resolution: 2.27 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 306468 / Symmetry type: POINT | ||||||||||||||||||||||||
| Refinement | Highest resolution: 2.27 Å Stereochemistry target values: REAL-SPACE (WEIGHTED MAP SUM AT ATOM CENTERS) | ||||||||||||||||||||||||
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FIELD EMISSION GUN