Summary information and primary citation

PDB-id
6whi; SNAP-derived features in text and JSON formats; DNAproDB
Class
immune system-DNA-RNA
Method
cryo-EM (4.2 Å)
Summary
Cryo-electron microscopy structure of the type i-f crispr RNA-guided surveillance complex bound to the anti-crispr acrif9
Reference
Hirschi M, Lu WT, Santiago-Frangos A, Wilkinson R, Golden SM, Davidson AR, Lander GC, Wiedenheft B (2020): "AcrIF9 tethers non-sequence specific dsDNA to the CRISPR RNA-guided surveillance complex." Nat Commun, 11, 2730. doi: 10.1038/s41467-020-16512-1.
Abstract
Bacteria have evolved sophisticated adaptive immune systems, called CRISPR-Cas, that provide sequence-specific protection against phage infection. In turn, phages have evolved a broad spectrum of anti-CRISPRs that suppress these immune systems. Here we report structures of anti-CRISPR protein IF9 (AcrIF9) in complex with the type I-F CRISPR RNA-guided surveillance complex (Csy). In addition to sterically blocking the hybridization of complementary dsDNA to the CRISPR RNA, our results show that AcrIF9 binding also promotes non-sequence-specific engagement with dsDNA, potentially sequestering the complex from target DNA. These findings highlight the versatility of anti-CRISPR mechanisms utilized by phages to suppress CRISPR-mediated immune systems.

Cartoon-block schematics in six views (download the tarball)

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