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Open data
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Basic information
| Entry | Database: PDB / ID: 7sbb | ||||||
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| Title | Structure of type I-D Cascade bound to a ssRNA target | ||||||
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Keywords | RNA BINDING PROTEIN/RNA / CRISPR / Complex / Ribonucleoprotein complex / type I-D / type ID / type I / cyanobacteria / synechocystis / RNA binding protein / RNA BINDING PROTEIN-RNA complex | ||||||
| Function / homology | Function and homology informationCRISPR-associated protein Csc1 / CRISPR associated protein Csc3 / CRISPR-associated protein Csc2 / Csc2 Crispr Similarity search - Domain/homology | ||||||
| Biological species | ![]() synthetic construct (others) | ||||||
| Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 3.1 Å | ||||||
Authors | Schwartz, E.A. / Taylor, D.W. | ||||||
| Funding support | United States, 1items
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Citation | Journal: Nat Commun / Year: 2022Title: Structural rearrangements allow nucleic acid discrimination by type I-D Cascade. Authors: Evan A Schwartz / Tess M McBride / Jack P K Bravo / Daniel Wrapp / Peter C Fineran / Robert D Fagerlund / David W Taylor / ![]() Abstract: CRISPR-Cas systems are adaptive immune systems that protect prokaryotes from foreign nucleic acids, such as bacteriophages. Two of the most prevalent CRISPR-Cas systems include type I and type III. ...CRISPR-Cas systems are adaptive immune systems that protect prokaryotes from foreign nucleic acids, such as bacteriophages. Two of the most prevalent CRISPR-Cas systems include type I and type III. Interestingly, the type I-D interference proteins contain characteristic features of both type I and type III systems. Here, we present the structures of type I-D Cascade bound to both a double-stranded (ds)DNA and a single-stranded (ss)RNA target at 2.9 and 3.1 Å, respectively. We show that type I-D Cascade is capable of specifically binding ssRNA and reveal how PAM recognition of dsDNA targets initiates long-range structural rearrangements that likely primes Cas10d for Cas3' binding and subsequent non-target strand DNA cleavage. These structures allow us to model how binding of the anti-CRISPR protein AcrID1 likely blocks target dsDNA binding via competitive inhibition of the DNA substrate engagement with the Cas10d active site. This work elucidates the unique mechanisms used by type I-D Cascade for discrimination of single-stranded and double stranded targets. Thus, our data supports a model for the hybrid nature of this complex with features of type III and type I systems. | ||||||
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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 | 7sbb.cif.gz | 634 KB | Display | PDBx/mmCIF format |
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| PDB format | pdb7sbb.ent.gz | 518.2 KB | Display | PDB format |
| PDBx/mmJSON format | 7sbb.json.gz | Tree view | PDBx/mmJSON format | |
| Others | Other downloads |
-Validation report
| Arichive directory | https://data.pdbj.org/pub/pdb/validation_reports/sb/7sbb ftp://data.pdbj.org/pub/pdb/validation_reports/sb/7sbb | HTTPS FTP |
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-Related structure data
| Related structure data | ![]() 24976MC ![]() 7sbaC 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
-Protein , 4 types, 11 molecules ABCDEFGHIJK
| #1: Protein | Mass: 36527.109 Da / Num. of mol.: 7 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() #2: Protein | | Mass: 28942.748 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() #3: Protein | | Mass: 112067.508 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() #4: Protein | Mass: 17024.494 Da / Num. of mol.: 2 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() |
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-RNA chain , 2 types, 2 molecules XZ
| #5: RNA chain | Mass: 10700.537 Da / Num. of mol.: 1 / Source method: obtained synthetically / Source: (synth.) synthetic construct (others) |
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| #6: RNA chain | Mass: 13699.081 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() |
-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: Type I-D Cascade bound to a ssRNA target / Type: COMPLEX / Entity ID: all / Source: MULTIPLE SOURCES | |||||||||||||||||||||||||
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| Molecular weight | Value: 0.45 MDa / Experimental value: NO | |||||||||||||||||||||||||
| Buffer solution | pH: 7.5 | |||||||||||||||||||||||||
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| Specimen | Conc.: 0.16 mg/ml / Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES / Details: Monodisperse sample of elongated particles. | |||||||||||||||||||||||||
| Specimen support | Grid material: COPPER / Grid mesh size: 400 divisions/in. / Grid type: C-flat | |||||||||||||||||||||||||
| Vitrification | Instrument: FEI VITROBOT MARK IV / Cryogen name: ETHANE / Humidity: 100 % / Chamber temperature: 277 K Details: Blot force 0, blot time 4s, no wait time between sample application and blotting. |
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Electron microscopy imaging
| Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |
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| Microscopy | Model: FEI TITAN KRIOS |
| Electron gun | Electron source: FIELD EMISSION GUN / Accelerating voltage: 300 kV / Illumination mode: FLOOD BEAM |
| Electron lens | Mode: BRIGHT FIELD / Nominal magnification: 22500 X / Nominal defocus max: 2200 nm / Nominal defocus min: 1200 nm / Cs: 2.7 mm / C2 aperture diameter: 100 µm / Alignment procedure: COMA FREE |
| Specimen holder | Cryogen: NITROGEN / Specimen holder model: FEI TITAN KRIOS AUTOGRID HOLDER |
| Image recording | Average exposure time: 3 sec. / Electron dose: 41.2 e/Å2 / Film or detector model: GATAN K3 (6k x 4k) / Num. of grids imaged: 2 |
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Processing
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| CTF correction | Type: PHASE FLIPPING AND AMPLITUDE CORRECTION | ||||||||||||||||||||||||
| Particle selection | Num. of particles selected: 4100000 | ||||||||||||||||||||||||
| Symmetry | Point symmetry: C1 (asymmetric) | ||||||||||||||||||||||||
| 3D reconstruction | Resolution: 3.1 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 167000 / Symmetry type: POINT | ||||||||||||||||||||||||
| Atomic model building | Details: Model was built de novo using coot then flexibly refined using ISOLDE. |
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About Yorodumi






United States, 1items
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gel filtration
