8F3K | pdb_00008f3k

Anti-CRISPR Protein AcrIIC5 Inhibits CRISPR-Cas9 by Occupying the Target DNA Binding Pocket.

(2023) J Mol Biology 435: 167991-167991

• PubMed: 36736884 Search on PubMed
• DOI: https://doi.org/10.1016/j.jmb.2023.167991
• Primary Citation of Related Structures:  
  8F3K


• PubMed Abstract: 
  

  Anti-CRISPR proteins inhibit CRISPR-Cas immune systems through diverse mechanisms. Previously, the anti-CRISPR protein AcrIIC5 _Smu was shown to potently inhibit a type II-C Cas9 from Neisseria meningitidis (Nme1Cas9). In this work, we explore the mechanism of activity of the AcrIIC5 homologue from Neisseria chenwenguii (AcrIIC5 _Nch ) and show that it prevents Cas9 binding to target DNA. We show that AcrIIC5 _Nch targets the PAM-interacting domain (PID) of Nme1Cas9 for inhibition, agreeing with previous findings for AcrIIC5 _Smu , and newly establish that strong binding of the anti-CRISPR requires guide RNA be pre-loaded on Cas9. We determined the crystal structure of AcrIIC5 _Nch using X-ray crystallography and identified amino acid residues that are critical for its function. Using a protein docking algorithm we show that AcrIIC5 _Nch likely occupies the Cas9 DNA binding pocket, thereby inhibiting target DNA binding through a mechanism similar to that previously described for AcrIIA2 and AcrIIA4.

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Organizational Affiliation: 

Department of Biochemistry, University of Toronto, 661 University Avenue, Suite 1600, Toronto, Ontario M5G 1M1, Canada. Electronic address: https://twitter.com/s1hwang_21.