A beta subtype methylase, recognizes the double-stranded sequence 5'-GANTC-3', methylates A-2 on both strands, and protects the DNA from cleavage by the HhaII endonuclease. a 2'-deoxyadenosine in DNA + S-adenosyl-L-methionine = an N(6)-methyl-2'-deoxyadenosine in DNA + H(+) + S-adenosyl-L-homocysteine Belongs to the N(4)/N(6)-methyltransferase family. Strain ATCC 10014 was originally thought to originate from H.haemolyticus.