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Open data
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Basic information
| Entry | Database: PDB / ID: 9jsp | |||||||||||||||||||||||||||||||||||||||
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| Title | inactive NbaSPARDA complexes | |||||||||||||||||||||||||||||||||||||||
Components |
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Keywords | RNA BINDING PROTEIN/RNA/DNA / protein / RNA / DNA / RNA BINDING PROTEIN-RNA-DNA complex | |||||||||||||||||||||||||||||||||||||||
| Function / homology | DNA / DNA (> 10) / RNA / RNA (> 10) Function and homology information | |||||||||||||||||||||||||||||||||||||||
| Biological species | Novosphingopyxis baekryungensis DSM 16222 (bacteria) | |||||||||||||||||||||||||||||||||||||||
| Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 3.34 Å | |||||||||||||||||||||||||||||||||||||||
Authors | Zhuang, L. | |||||||||||||||||||||||||||||||||||||||
| Funding support | 1items
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Citation | Journal: Cell Res / Year: 2025Title: Target DNA-induced filament formation and nuclease activation of SPARDA complex. Authors: Feng Wang / Haijiang Xu / Chendi Zhang / Jialin Xue / Zhuang Li / ![]() Abstract: The short Argonaute-based bacterial defense system, SPARDA (Short Prokaryotic Argonaute and DNase/RNase-APAZ), utilizes guide RNA to target invading complementary DNA and exhibits collateral nuclease ...The short Argonaute-based bacterial defense system, SPARDA (Short Prokaryotic Argonaute and DNase/RNase-APAZ), utilizes guide RNA to target invading complementary DNA and exhibits collateral nuclease activity, leading to cell death or dormancy. However, its detailed mechanisms remain poorly understood. In this study, we investigated the SPARDA system from Novosphingopyxis baekryungensis (NbaSPARDA) and discovered an unexpected filament configuration upon target DNA binding, which strongly correlated with collateral nuclease activity. Filament formation and nuclease activation require a guide-target heteroduplex of sufficient length with perfect complementarity at the central region. A series of cryo-EM structures of NbaSPARDA complexes, loaded with guide RNA, target DNA of varying lengths, and substrate ssDNA, were determined at ~3.0 Å resolution. Structural analyses indicated that guide RNA binding induces dimerization of the NbaSPARDA complex, while target DNA engagement disrupts this dimerization. Further propagation of the guide-target heteroduplex triggers filament formation through a checkpoint mechanism. The NbaSPARDA filament consists of a backbone formed by interlocking short Argonaute proteins, with an inner layer composed of DREN nuclease domains. Filament formation leads to tetramerization of the monomeric DREN nuclease domain, activating its collateral nuclease activity against environmental nucleic acids - a feature leveraged for molecular diagnostics. For bacteria heterologously expressing the NbaSPARDA system, defense against invading bacteriophages and plasmids relies on filament formation. Collectively, these findings illustrate the detailed working mechanism of the NbaSPARDA complex and highlight the importance of its filament formation in host 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 | 9jsp.cif.gz | 150.4 KB | Display | PDBx/mmCIF format |
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| PDB format | pdb9jsp.ent.gz | 109.3 KB | Display | PDB format |
| PDBx/mmJSON format | 9jsp.json.gz | Tree view | PDBx/mmJSON format | |
| Others | Other downloads |
-Validation report
| Arichive directory | https://data.pdbj.org/pub/pdb/validation_reports/js/9jsp ftp://data.pdbj.org/pub/pdb/validation_reports/js/9jsp | HTTPS FTP |
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-Related structure data
| Related structure data | ![]() 61780MC ![]() 9jsbC ![]() 9jszC ![]() 9jt2C 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: 54492.809 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Source: (gene. exp.) Novosphingopyxis baekryungensis DSM 16222 (bacteria)Production host: ![]() |
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| #2: Protein | Mass: 50419.645 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Source: (gene. exp.) Novosphingopyxis baekryungensis DSM 16222 (bacteria)Production host: ![]() |
| #3: RNA chain | Mass: 6390.879 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Source: (gene. exp.) Novosphingopyxis baekryungensis DSM 16222 (bacteria)Production host: ![]() |
| #4: DNA chain | Mass: 3997.607 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Source: (gene. exp.) Novosphingopyxis baekryungensis DSM 16222 (bacteria)Production host: ![]() |
| #5: Chemical | ChemComp-MG / |
| Has ligand of interest | Y |
| Has protein modification | N |
-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: pro-RNA-13DNA / Type: COMPLEX / Entity ID: #1-#4 / Source: RECOMBINANT |
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| Source (natural) | Organism: Novosphingopyxis baekryungensis DSM 16222 (bacteria) |
| Source (recombinant) | Organism: ![]() |
| 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: Talos Arctica / Image courtesy: FEI Company |
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| Microscopy | Model: FEI TALOS ARCTICA |
| Electron gun | Electron source: FIELD EMISSION GUN / Accelerating voltage: 300 kV / Illumination mode: FLOOD BEAM |
| Electron lens | Mode: BRIGHT FIELD / Nominal defocus max: 2200 nm / Nominal defocus min: 1200 nm |
| Image recording | Electron dose: 54 e/Å2 / Film or detector model: GATAN K3 BIOQUANTUM (6k x 4k) |
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Processing
| EM software | Name: PHENIX / Category: model refinement | ||||||||||||||||||||||||
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| CTF correction | Type: NONE | ||||||||||||||||||||||||
| 3D reconstruction | Resolution: 3.34 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 213852 / Symmetry type: POINT | ||||||||||||||||||||||||
| Refine LS restraints |
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About Yorodumi




Novosphingopyxis baekryungensis DSM 16222 (bacteria)
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FIELD EMISSION GUN