 But, for instance, when AcrF1 and AcrF2 are found (anti-CRISPR proteins), these interact with Cas7f and Cas8f-Cas5f, respectively, not allowing the binding to the phage DNA.Moreover, the cleaving of the target is prevented by the union between AcrF3 and Cas3.The majority of Acr genes are located next to anti-CRISPR-associated (Aca) genes, which encode proteins with a helix-turn-helix DNA-binding motif.