A beta subtype methylase that recognizes the double-stranded sequence 5'-GAAGA-3', methylates A-5 on the top strand, and protects the DNA from cleavage by the MboII endonuclease. It is not known if the cytosine of the complementary sequence TCTTC is also methylated by this enzyme. a 2'-deoxyadenosine in DNA + S-adenosyl-L-methionine = an N(6)-methyl-2'-deoxyadenosine in DNA + H(+) + S-adenosyl-L-homocysteine At low concentration exists as a monomer and homodimer (PubMed:12954781). Probably binds to DNA as a monomer (Probable). Belongs to the N(4)/N(6)-methyltransferase family.