+
Open data
-
Basic information
| Entry | Database: PDB / ID: 9vjb | |||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Title | Type II-A CRISPR integrase pre-integration complex | |||||||||||||||||||||||||||
Components |
| |||||||||||||||||||||||||||
Keywords | DNA BINDING PROTEIN/DNA / CRISPR / Cas1 / Cas2 / Csn2 / DNA BINDING PROTEIN-DNA complex | |||||||||||||||||||||||||||
| Function / homology | Function and homology informationmaintenance of CRISPR repeat elements / RNA endonuclease activity / DNA endonuclease activity / defense response to virus / Hydrolases; Acting on ester bonds / hydrolase activity / DNA binding / metal ion binding Similarity search - Function | |||||||||||||||||||||||||||
| Biological species | ![]() synthetic construct (others) | |||||||||||||||||||||||||||
| Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 3.76 Å | |||||||||||||||||||||||||||
Authors | Li, Z.X. / Li, Y.T. / Lu, M.L. / Xiao, Y.B. | |||||||||||||||||||||||||||
| Funding support | China, 3items
| |||||||||||||||||||||||||||
Citation | Journal: Mol Cell / Year: 2026Title: Structural basis for Cas9-directed spacer acquisition in type II-A CRISPR-Cas systems. Authors: Zhaoxing Li / Yutao Li / Jianping Kong / Qianqian Wu / Pingping Huang / Yu Zhang / Wanqian Wu / Meirong Chen / Yongfeng Liu / HanFeng Lin / Liqiu Hou / Gongyu Liu / Ting Zeng / Yutong He / ...Authors: Zhaoxing Li / Yutao Li / Jianping Kong / Qianqian Wu / Pingping Huang / Yu Zhang / Wanqian Wu / Meirong Chen / Yongfeng Liu / HanFeng Lin / Liqiu Hou / Gongyu Liu / Ting Zeng / Yutong He / Chunyi Hu / Zhenhuang Yang / Meiling Lu / Min Luo / Yibei Xiao / ![]() Abstract: CRISPR-Cas systems confer prokaryotic immunity by integrating foreign DNA (prespacers) into host arrays. Type II-A systems employ Cas9 for protospacer-adjacent motif (PAM) recognition and coordinate ...CRISPR-Cas systems confer prokaryotic immunity by integrating foreign DNA (prespacers) into host arrays. Type II-A systems employ Cas9 for protospacer-adjacent motif (PAM) recognition and coordinate with Csn2 and the Cas1-Cas2 integrase during spacer acquisition, yet their structural basis remains unresolved. Here, we report cryo-electron microscopy (cryo-EM) structures of the Enterococcus faecalis Cas9-Csn2-Cas1-Cas2 supercomplex in apo and DNA-bound states. The apo state (Cas9₂-Csn2₈-Cas1₈-Cas2₄) is a resting complex, while DNA binding forms a prespacer-catching complex threading DNA through Csn2's channel, enabling Cas9 to interrogate the PAM sequence while sliding along the DNA. Cas9 and Csn2 jointly define a 30-bp DNA segment matching the prespacer length. Cas9 dissociation triggers structural reconfiguration of the Csn2-Cas1-Cas2 assembly. This exposes the PAM-proximal DNA, allowing Cas1-Cas2 to bind the exposed site for subsequent prespacer processing and directional integration. These findings reveal how Cas9, Csn2, and Cas1-Cas2 couple PAM recognition with prespacer selection, ensuring fidelity during adaptation. | |||||||||||||||||||||||||||
| History |
|
-
Structure visualization
| Structure viewer | Molecule: Molmil Jmol/JSmol |
|---|
-
Downloads & links
-
Download
| PDBx/mmCIF format | 9vjb.cif.gz | 298.2 KB | Display | PDBx/mmCIF format |
|---|---|---|---|---|
| PDB format | pdb9vjb.ent.gz | 237.5 KB | Display | PDB format |
| PDBx/mmJSON format | 9vjb.json.gz | Tree view | PDBx/mmJSON format | |
| Others | Other downloads |
-Validation report
| Arichive directory | https://data.pdbj.org/pub/pdb/validation_reports/vj/9vjb ftp://data.pdbj.org/pub/pdb/validation_reports/vj/9vjb | HTTPS FTP |
|---|
-Related structure data
| Related structure data | ![]() 65109MC ![]() 9vj8C ![]() 9vj9C ![]() 9vjaC M: map data used to model this data C: citing same article ( |
|---|---|
| Similar structure data | Similarity search - Function & homology F&H Search |
-
Links
-
Assembly
| Deposited unit | ![]()
|
|---|---|
| 1 |
|
-
Components
-CRISPR-associated ... , 2 types, 3 molecules IJN
| #2: Protein | Mass: 33492.625 Da / Num. of mol.: 2 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() References: UniProt: A0A3N3GDE4, Hydrolases; Acting on ester bonds #5: Protein | | Mass: 12977.047 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() References: UniProt: A0A3N3FLR9, Hydrolases; Acting on ester bonds |
|---|
-DNA chain , 2 types, 2 molecules XY
| #3: DNA chain | Mass: 15468.875 Da / Num. of mol.: 1 / Source method: obtained synthetically / Source: (synth.) synthetic construct (others) |
|---|---|
| #4: DNA chain | Mass: 15928.584 Da / Num. of mol.: 1 / Source method: obtained synthetically / Source: (synth.) synthetic construct (others) |
-Protein / Non-polymers , 2 types, 10 molecules ABCD

| #1: Protein | Mass: 25433.090 Da / Num. of mol.: 4 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() #6: Chemical | ChemComp-CA / |
|---|
-Details
| Has ligand of interest | N |
|---|---|
| Has protein modification | N |
-Experimental details
-Experiment
| Experiment | Method: ELECTRON MICROSCOPY |
|---|---|
| EM experiment | Aggregation state: PARTICLE / 3D reconstruction method: single particle reconstruction |
-
Sample preparation
| Component | Name: E. faecalis Csn2/Cas1/Cas2 pre-integration complex, conformation 1 Type: COMPLEX / Entity ID: #1-#2, #5, #3-#4 / Source: MULTIPLE SOURCES |
|---|---|
| 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 |
-
Electron microscopy imaging
| Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |
|---|---|
| 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 magnification: 130000 X / Nominal defocus max: 2400 nm / Nominal defocus min: 1000 nm |
| Image recording | Electron dose: 45 e/Å2 / Film or detector model: FEI FALCON IV (4k x 4k) |
-
Processing
| EM software |
| |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| CTF correction | Type: PHASE FLIPPING AND AMPLITUDE CORRECTION | |||||||||
| 3D reconstruction | Resolution: 3.76 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 50477 / Symmetry type: POINT | |||||||||
| Refinement | Highest resolution: 3.76 Å Stereochemistry target values: REAL-SPACE (WEIGHTED MAP SUM AT ATOM CENTERS) |
Movie
Controller
About Yorodumi






China, 3items
Citation







PDBj








































FIELD EMISSION GUN