A high‐resolution (1.2 Å) crystal structure of the anti‐CRISPR protein AcrIF9. Issue 12 (5th November 2020) - Kim, Gi Eob
Abstract : Prokaryotic adaptive immunity by CRISPR‐Cas systems, which confer resistance to foreign genetic elements, has been used by bacteria to combat viruses. To cope, viruses evolved multiple anti‐CRISPR proteins, which can inhibit system function through various mechanisms. Although the structures and mechanisms of several anti‐CRISPR proteins have been elucidated, those of the AcrIF9 family have not yet been identified. To understand the molecular basis underlying AcrIF9 anti‐CRISPR function, we determined the 1.2 Å crystal structure of AcrIF9. Structural and biochemical studies showed that AcrIF9 exists in monomeric form in solution and can directly interact with DNA using a positively charged cleft. Based on analysis of the structure, we suggest part of the anti‐CRISPR molecular mechanism by AcrIF9. Abstract : This study determined the 1.2 Å high‐resolution crystal structure of AcrIF9 for the purpose of understanding the molecular basis underlying its anti‐CRISPR function. This high‐resolution crystal structure was compared with the identified structure of the cryo‐electron microscopy structure of AcrIF9 associated with the cascade complex to analyze feature similarities and differences.