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AcrIF9 tethers non-sequence specific dsDNA to the CRISPR RNA-guided surveillance complex.

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.

SUBMITTER: Hirschi M

PROVIDER: S-EPMC7264359 | biostudies-literature | 2020 Jun

REPOSITORIES: biostudies-literature

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AcrIF9 tethers non-sequence specific dsDNA to the CRISPR RNA-guided surveillance complex.

Hirschi Marscha M Lu Wang-Ting WT Santiago-Frangos Andrew A Wilkinson Royce R Golden Sarah M SM Davidson Alan R AR Lander Gabriel C GC Wiedenheft Blake B

Nature communications 20200601 1

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 A ...[more]

PMID: 32483187

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