RNA Therapeutics Institute; Program in Molecular Medicine
Biochemistry, Biophysics, and Structural Biology | Genetics and Genomics | Immunology and Infectious Disease
CRISPR-Cas adaptive immune systems function to protect bacteria from invasion by foreign genetic elements. The CRISPR-Cas9 system has been widely adopted as a powerful genome-editing tool, and phage-encoded inhibitors, known as anti-CRISPRs, offer a means of regulating its activity. Here, we report the crystal structures of anti-CRISPR protein AcrIIC2Nme alone and in complex with Nme1Cas9. We demonstrate that AcrIIC2Nme inhibits Cas9 through interactions with the positively charged bridge helix, thereby preventing sgRNA loading. In vivo phage plaque assays and in vitro DNA cleavage assays show that AcrIIC2Nme mediates its activity through a large electronegative surface. This work shows that anti-CRISPR activity can be mediated through the inhibition of Cas9 complex assembly.
Bacteriophages, CRISPR-Cas systems, X-ray crystallography
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DOI of Published Version
Nat Commun. 2019 Jun 26;10(1):2806. doi: 10.1038/s41467-019-10577-3. Link to article on publisher's site
Thavalingam A, Sontheimer EJ, Wang Y, Maxwell KL. (2019). Inhibition of CRISPR-Cas9 ribonucleoprotein complex assembly by anti-CRISPR AcrIIC2. Open Access Publications by UMass Chan Authors. https://doi.org/10.1038/s41467-019-10577-3. Retrieved from https://escholarship.umassmed.edu/oapubs/3893
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.