AcrIF9 tethers non-sequence specific dsDNA to the CRISPR RNA-guided surveillance complex.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 32483187.
- Also identified by DOI 10.1038/s41467-020-16512-1 and PMC identifier 7264359.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
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.
Medical subject headings
- Bacteria
- Bacteriophages
- CRISPR-Cas Systems
- DNA
- RNA, Guide, CRISPR-Cas Systems
- Viral Proteins