The anti-CRISPR protein AcrIE8.1 blocks the type I-E CRISPR system by binding to a key Cascade protein

The crystal structure of AcrIE8.1 reveals it binds to Cas11, disrupting the CRISPR-Cas system.

• AcrIE8.1 is an uncharacterized anti-CRISPR protein that inhibits the CRISPR interference pathway.
• The binding of AcrIE8.1 to Cas11 suggests a unique mechanism of action compared to other anti-CRISPR proteins.
• AcrIE8.1 has a compact structure with a specific interface for binding to Cas11.
• These findings underscore the importance of Cas11 as a target for immune evasion by bacteriophages.

Simplified