 Furthermore, the locus of the genes codifying these type I-E proteins was really close to the one responsible for the type I-F proteins expression in the same group of phages, leading to the conclusion that both types of proteins worked together.However, these first nine proteins shared no common sequence motifs, which would have made easier the identification of new Anti-CRISPR protein families.Later on, it was seen that phages that produced such proteins also encoded a putative transcriptional regulator named Aca 1 (anti-CRISPR associated 1) which was genetically located really close to the anti-CRISPR genes.