Table shows that tau protein contains DNA methylase adenine-specific and N6-adenine-specific DNA methyltransferase N-terminal domains. In particular, tau protein has N-6 adenine (A)-specific DNA methyltransferase activity mainly at the beginning and end of the chain. These are the sites located at the extremities of the methylated specific region on DNA. (3) RNA-guided HNH Cas9 enzyme domains HNH endonuclease 5 (IPR029471) suggests the nucleolytic function of these proteins. Bacterial HNH domains can function as both site-specific DNA nucleases (e.g., homing nucleases or the RNA-guided DNA endonuclease Cas9) and non-specific nucleases (e.g., colicins, a subgroup of bacterial toxins).