Discovery and Characterization of Cas9 Inhibitors Disseminated across Seven Bacterial Phyla (Cell Host & Microbe)

Uribe et al. developed a high-throughput approach to screen for type II-A CRISPR-Cas inhibitors in metagenomic libraries based on their functional activity rather than sequence homology or genetic context. This approach led to the discovery of four novel anti-CRISPR proteins, homologs of which are widely distributed across seven bacterial phyla.