De novo design of potent CRISPR–Cas13 inhibitors

CRISPR-Cas systems are transformative tools for gene editing that can be tuned or controlled by anti-CRISPRs (Acrs)-phage-derived inhibitors that regulate CRISPR-Cas activity. However, Acrs that can inhibit biotechnologically relevant CRISPR systems are relatively rare and challenging to discover. To overcome this limitation, we describe a highly successful and rapid approach that leverages de novo protein design to develop new-to-nature proteins for controlling CRISPR-Cas activity. Here, using Leptotrichia buccalis CRISPR-Cas13a as a representative example, we demonstrate that Acrs designed using artificial intelligence (AIcrs) are capable of highly potent and specific inhibition of CRISPR-Cas13a nuclease activity. We present a comprehensive workflow for design validation and demonstrate AIcr functionality in controlling CRISPR-Cas13 activity in bacterial and human cells. The ability to design bespoke inhibitors of Cas effectors will contribute to the ongoing development of CRISPR-Cas tools in diverse applications across research, medicine, agriculture and microbiology.