9VJ9
Type I-A CRISPR integrase prespacer catching complex, State I
Summary for 9VJ9
| Entry DOI | 10.2210/pdb9vj9/pdb |
| EMDB information | 65107 65231 |
| Descriptor | Type II-A CRISPR-associated protein Csn2, CRISPR-associated endonuclease Cas1, DNA (51-MER), ... (7 entities in total) |
| Functional Keywords | crispr, cas9, cas1, csn2 dna binding protein, dna binding protein/dna/rna, dna binding protein-dna-rna complex |
| Biological source | Enterococcus faecalis More |
| Total number of polymer chains | 11 |
| Total formula weight | 399877.20 |
| Authors | |
| Primary citation | Li, Z.,Li, Y.,Kong, J.,Wu, Q.,Huang, P.,Zhang, Y.,Wu, W.,Chen, M.,Liu, Y.,Lin, H.,Hou, L.,Liu, G.,Zeng, T.,He, Y.,Hu, C.,Yang, Z.,Lu, M.,Luo, M.,Xiao, Y. Structural basis for Cas9-directed spacer acquisition in type II-A CRISPR-Cas systems. Mol.Cell, 86:805-816.e4, 2026 Cited by PubMed 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 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. PubMed: 41702404DOI: 10.1016/j.molcel.2026.01.024 PDB entries with the same primary citation |
| Experimental method | ELECTRON MICROSCOPY (2.96 Å) |
Structure validation
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