 This regulatory protein is supposed to be the responsible for the anti-CRISPR gene expression during the infectious cycle of the phage, therefore, both types of proteins (anti-CRISPR and Aca1) seem to work together as a single mechanism.After some studies, a similar amino-acid sequence to that of Aca1 was found, leading to the discovery of Aca2, a new family of Aca proteins.Aca2 also revealed the existence of five new groups of type I-F anti-CRISPR proteins due to their genomic proximity