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Open data
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Basic information
Entry | Database: PDB / ID: 8dfa | |||||||||
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Title | type I-C Cascade bound to ssDNA target | |||||||||
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![]() | DNA BINDING PROTEIN/DNA/RNA / CRISPR / type I-C / Cascade / ssDNA target / DNA BINDING PROTEIN / DNA BINDING PROTEIN-DNA-RNA complex | |||||||||
Function / homology | ![]() maintenance of CRISPR repeat elements / endonuclease activity / defense response to virus / Hydrolases; Acting on ester bonds / RNA binding Similarity search - Function | |||||||||
Biological species | ![]() ![]() | |||||||||
Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 2.8 Å | |||||||||
![]() | O'Brien, R.E. / Bravo, J.P.K. / Ramos, D. / Hibshman, G.N. / Wright, J.T. / Taylor, D.W. | |||||||||
Funding support | ![]()
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![]() | ![]() Title: Structural snapshots of R-loop formation by a type I-C CRISPR Cascade. Authors: Roisin E O'Brien / Jack P K Bravo / Delisa Ramos / Grace N Hibshman / Jacquelyn T Wright / David W Taylor / ![]() Abstract: Type I CRISPR-Cas systems employ multi-subunit Cascade effector complexes to target foreign nucleic acids for destruction. Here, we present structures of D. vulgaris type I-C Cascade at various ...Type I CRISPR-Cas systems employ multi-subunit Cascade effector complexes to target foreign nucleic acids for destruction. Here, we present structures of D. vulgaris type I-C Cascade at various stages of double-stranded (ds)DNA target capture, revealing mechanisms that underpin PAM recognition and Cascade allosteric activation. We uncover an interesting mechanism of non-target strand (NTS) DNA stabilization via stacking interactions with the "belly" subunits, securing the NTS in place. This "molecular seatbelt" mechanism facilitates efficient R-loop formation and prevents dsDNA reannealing. Additionally, we provide structural insights into how two anti-CRISPR (Acr) proteins utilize distinct strategies to achieve a shared mechanism of type I-C Cascade inhibition by blocking PAM scanning. These observations form a structural basis for directional R-loop formation and reveal how different Acr proteins have converged upon common molecular mechanisms to efficiently shut down CRISPR immunity. | |||||||||
History |
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Structure visualization
Structure viewer | Molecule: ![]() ![]() |
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Downloads & links
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Download
PDBx/mmCIF format | ![]() | 1.1 MB | Display | ![]() |
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PDB format | ![]() | 921.5 KB | Display | ![]() |
PDBx/mmJSON format | ![]() | Tree view | ![]() | |
Others | ![]() |
-Validation report
Summary document | ![]() | 1.3 MB | Display | ![]() |
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Full document | ![]() | 1.4 MB | Display | |
Data in XML | ![]() | 91.7 KB | Display | |
Data in CIF | ![]() | 139.8 KB | Display | |
Arichive directory | ![]() ![]() | HTTPS FTP |
-Related structure data
Related structure data | ![]() 27403MC ![]() 8dejC ![]() 8dexC ![]() 8dfoC ![]() 8dfsC M: map data used to model this data C: citing same article ( |
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Similar structure data | Similarity search - Function & homology ![]() |
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Links
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Assembly
Deposited unit | ![]()
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Components
-Protein , 2 types, 8 molecules ABCDEFGH
#1: Protein | Mass: 25977.857 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() Strain: ATCC 29579 / DSM 644 / NCIMB 8303 / VKM B-1760 / Hildenborough Gene: DVUA0130 / Production host: ![]() ![]() References: UniProt: Q72WF9, Hydrolases; Acting on ester bonds |
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#2: Protein | Mass: 32358.912 Da / Num. of mol.: 7 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() Strain: ATCC 29579 / DSM 644 / NCIMB 8303 / VKM B-1760 / Hildenborough Gene: DVUA0132 / Production host: ![]() ![]() |
-CRISPR-associated protein, CT1133 ... , 2 types, 3 molecules IJK
#3: Protein | Mass: 68123.219 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() Strain: ATCC 29579 / DSM 644 / NCIMB 8303 / VKM B-1760 / Hildenborough Gene: DVUA0131 / Production host: ![]() ![]() |
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#4: Protein | Mass: 14017.981 Da / Num. of mol.: 2 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() Strain: ATCC 29579 / DSM 644 / NCIMB 8303 / VKM B-1760 / Hildenborough Gene: DVUA0131 / Production host: ![]() ![]() |
-RNA chain / DNA/RNA hybrid , 2 types, 2 molecules LN
#5: RNA chain | Mass: 14817.853 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() ![]() |
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#6: DNA/RNA hybrid | Mass: 5517.567 Da / Num. of mol.: 1 / Source method: obtained synthetically / Source: (synth.) ![]() |
-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-C Cascade bound to ssDNA / Type: COMPLEX / Entity ID: all / Source: RECOMBINANT |
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Molecular weight | Experimental value: NO |
Source (natural) | Organism: ![]() |
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
Microscopy | Model: TFS GLACIOS |
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Electron gun | Electron source: ![]() |
Electron lens | Mode: BRIGHT FIELD / Nominal defocus max: 2200 nm / Nominal defocus min: 1200 nm |
Image recording | Electron dose: 40.5 e/Å2 / Film or detector model: FEI FALCON IV (4k x 4k) |
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Processing
Software | Name: PHENIX / Version: 1.20.1_4487: / Classification: refinement | ||||||||||||||||||||||||
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CTF correction | Type: PHASE FLIPPING AND AMPLITUDE CORRECTION | ||||||||||||||||||||||||
3D reconstruction | Resolution: 2.8 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 174004 / Symmetry type: POINT | ||||||||||||||||||||||||
Refine LS restraints |
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