CRISPR-Cas systems are sophisticated adaptive immune systems in bacteria and archaea to protect them from phage infection and have been repurposed for genome editing and molecular diagnostics applications. In response, phages have evolved anti-CRISPR (Acr) proteins to inhibit the CRISPR-Cas systems and to make genome editing safer and more precise. We are interested in the molecular mechanism for CRISPR effectors and their inhibition by Acr proteins. Our approach combines single-particle cryo-EM, crystallography, computational methods, and biochemical assays.


                      Cas12a–crRNA–AcrVA1                                                 Cas12a–crRNA–AcrVA4