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Open data
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Basic information
| Entry | Database: PDB / ID: 9h4l | ||||||||||||||||||||||||
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| Title | dCas9 bound to off-target 2 EMX1-1 (-)SC DNA minicircle | ||||||||||||||||||||||||
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Keywords | HYDROLASE / dCas9 / Cas9 / on-target / off-target / EMX1-1 / negatively supercoiled / diamond ring | ||||||||||||||||||||||||
| Function / homology | Function and homology informationmaintenance of CRISPR repeat elements / 3'-5' exonuclease activity / DNA endonuclease activity / defense response to virus / Hydrolases; Acting on ester bonds / DNA binding / RNA binding / metal ion binding Similarity search - Function | ||||||||||||||||||||||||
| Biological species | Streptococcus pyogenes (bacteria)synthetic construct (others) | ||||||||||||||||||||||||
| Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 3.9 Å | ||||||||||||||||||||||||
Authors | Smith, Q.M. / Rueda, D. | ||||||||||||||||||||||||
| Funding support | United Kingdom, 1items
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Citation | Journal: Nature / Year: 2026Title: Structural basis of supercoiling-induced CRISPR-Cas9 off-target activity. Authors: Quentin M Smith / Sylvia Whittle / Ricardo J Aramayo / Daniel E Rollins / Adam S B Jalal / Deborah I Egharevba / Kyle L Morris / Alice L B Pyne / David S Rueda / ![]() Abstract: CRISPR-Cas9 is a powerful genome-editing tool, but genome-wide off-target activity can hinder therapeutic applications. Negative supercoiling ((-)SC) has been implicated in off-target activity, but a ...CRISPR-Cas9 is a powerful genome-editing tool, but genome-wide off-target activity can hinder therapeutic applications. Negative supercoiling ((-)SC) has been implicated in off-target activity, but a molecular-level understanding is lacking. Here, using (-)SC DNA minicircles, we observe supercoiling-driven structural defects in the DNA that are resolved by Cas9 binding. Cryo-electron microscopy structures of Cas9 bound in both the on-target and off-target configurations highlight that the Cas9 HNH domain is poised in a more catalytically competent conformation. New DNA-RNA mismatch geometries are accommodated across the protospacer and structural plasticity in the protospacer adjacent motif distal region of the protospacer is topology dependent. Together, our study reveals the molecular basis for (-)SC-induced Cas9 targeting and provides a framework for the design of next-generation high-fidelity CRISPR effectors with topological context. | ||||||||||||||||||||||||
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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 | 9h4l.cif.gz | 283 KB | Display | PDBx/mmCIF format |
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| PDB format | pdb9h4l.ent.gz | 215.1 KB | Display | PDB format |
| PDBx/mmJSON format | 9h4l.json.gz | Tree view | PDBx/mmJSON format | |
| Others | Other downloads |
-Validation report
| Arichive directory | https://data.pdbj.org/pub/pdb/validation_reports/h4/9h4l ftp://data.pdbj.org/pub/pdb/validation_reports/h4/9h4l | HTTPS FTP |
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-Related structure data
| Related structure data | ![]() 51863MC ![]() 9h4jC ![]() 9h4kC ![]() 9h4mC 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: 158352.500 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Source: (gene. exp.) Streptococcus pyogenes (bacteria) / Gene: cas9, csn1, SPy_1046 / Production host: ![]() References: UniProt: Q99ZW2, Hydrolases; Acting on ester bonds |
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| #2: RNA chain | Mass: 28810.205 Da / Num. of mol.: 1 / Source method: obtained synthetically / Source: (synth.) synthetic construct (others) |
| #3: DNA chain | Mass: 5320.427 Da / Num. of mol.: 1 / Source method: obtained synthetically / Source: (synth.) synthetic construct (others) |
| #4: DNA chain | Mass: 2515.679 Da / Num. of mol.: 1 / Source method: obtained synthetically / Source: (synth.) synthetic construct (others) |
| 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: dCas9 EMX1-1 on-target complex on a negatively supercoiled DNA minicircle Type: COMPLEX / Entity ID: #2-#4, #1 / Source: RECOMBINANT |
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| Molecular weight | Value: 0.160 MDa / Experimental value: YES |
| Source (natural) | Organism: Streptococcus pyogenes (bacteria) |
| 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
| 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: 500 nm / Cs: 2.7 mm |
| Image recording | Electron dose: 41 e/Å2 / Film or detector model: GATAN K3 (6k x 4k) |
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Processing
| EM software | Name: PHENIX / Version: 1.20.1_4487: / Category: model refinement | ||||||||||||||||||||||||
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| CTF correction | Type: PHASE FLIPPING AND AMPLITUDE CORRECTION | ||||||||||||||||||||||||
| 3D reconstruction | Resolution: 3.9 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 667106 / Symmetry type: POINT | ||||||||||||||||||||||||
| Refine LS restraints |
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About Yorodumi




Streptococcus pyogenes (bacteria)
United Kingdom, 1items
Citation







PDBj

































































FIELD EMISSION GUN