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Open data
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Basic information
Entry | Database: PDB / ID: 8w1p | ||||||
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Title | Structure of Selenomonas sp. Cascade (SsCascade) | ||||||
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![]() | IMMUNE SYSTEM / CRISPR-Cas / Genome engineering / RNA-guided DNA endonuclease / Non-coding RNA / HNH nuclease | ||||||
Function / homology | DNA / DNA (> 10) / RNA / RNA (> 10)![]() | ||||||
Biological species | ![]() synthetic construct (others) | ||||||
Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 3.5 Å | ||||||
![]() | Hirano, S. / Zhang, F. | ||||||
Funding support | ![]()
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![]() | ![]() Title: Structural determinants of DNA cleavage by a CRISPR HNH-Cascade system. Authors: Seiichi Hirano / Han Altae-Tran / Soumya Kannan / Rhiannon K Macrae / Feng Zhang / ![]() Abstract: Canonical prokaryotic type I CRISPR-Cas adaptive immune systems contain a multicomponent effector complex called Cascade, which degrades large stretches of DNA via Cas3 helicase-nuclease activity. ...Canonical prokaryotic type I CRISPR-Cas adaptive immune systems contain a multicomponent effector complex called Cascade, which degrades large stretches of DNA via Cas3 helicase-nuclease activity. Recently, a highly precise subtype I-F1 CRISPR-Cas system (HNH-Cascade) was found that lacks Cas3, the absence of which is compensated for by the insertion of an HNH endonuclease domain in the Cas8 Cascade component. Here, we describe the cryo-EM structure of Selenomonas sp. HNH-Cascade (SsCascade) in complex with target DNA and characterize its mechanism of action. The Cascade scaffold is complemented by the HNH domain, creating a ring-like structure in which the unwound target DNA is precisely cleaved. This structure visualizes a unique hybrid of two extensible biological systems-Cascade, an evolutionary platform for programmable DNA effectors, and an HNH nuclease, an adaptive domain with a spectrum of enzymatic activity. | ||||||
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Structure visualization
Structure viewer | Molecule: ![]() ![]() |
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Downloads & links
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Download
PDBx/mmCIF format | ![]() | 954.4 KB | Display | ![]() |
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PDB format | ![]() | Display | ![]() | |
PDBx/mmJSON format | ![]() | Tree view | ![]() | |
Others | ![]() |
-Validation report
Summary document | ![]() | 1.4 MB | Display | ![]() |
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Full document | ![]() | 1.4 MB | Display | |
Data in XML | ![]() | 76.6 KB | Display | |
Data in CIF | ![]() | 120.6 KB | Display | |
Arichive directory | ![]() ![]() | HTTPS FTP |
-Related structure data
Related structure data | ![]() 43729MC 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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1 |
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Components
-Protein , 4 types, 9 molecules ABCDEFGHI
#1: Protein | Mass: 38700.172 Da / Num. of mol.: 6 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() ![]() #2: Protein | | Mass: 43706.289 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Details: This protein is histidine tagged at N-terminal region from residues 1 to 41. Residues 42 to 385 are derived from natural Cas8 protein sequences. Source: (gene. exp.) ![]() ![]() ![]() #3: Protein | | Mass: 28703.135 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() ![]() #4: Protein | | Mass: 20735.873 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() ![]() |
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-DNA chain , 2 types, 2 molecules NT
#5: DNA chain | Mass: 20484.176 Da / Num. of mol.: 1 / Source method: obtained synthetically / Source: (synth.) synthetic construct (others) |
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#7: DNA chain | Mass: 20202.930 Da / Num. of mol.: 1 / Source method: obtained synthetically / Source: (synth.) synthetic construct (others) |
-RNA chain , 1 types, 1 molecules R
#6: RNA chain | Mass: 19746.777 Da / Num. of mol.: 1 / Source method: obtained synthetically / Source: (synth.) synthetic construct (others) |
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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: Target DNA-bound SsCascade / 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
Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |
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Microscopy | Model: FEI TITAN KRIOS |
Electron gun | Electron source: ![]() |
Electron lens | Mode: BRIGHT FIELD / Nominal defocus max: 2500 nm / Nominal defocus min: 800 nm |
Image recording | Electron dose: 1.05 e/Å2 / Film or detector model: GATAN K3 (6k x 4k) |
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Processing
CTF correction | Type: NONE | ||||||||||||||||||||||||
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3D reconstruction | Resolution: 3.5 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 80908 / Symmetry type: POINT | ||||||||||||||||||||||||
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