An alpha subtype methylase that recognizes the double-stranded sequence 5'-GATC-3' and methylates A-2 on both strands (Probable) (PubMed:12654995). Although it shares sequence specificity with a number of type II restriction endonucleases and methylases, it is thought to act in methyl-directed mismatch repair, initiation of chromosome replication and gene expression. 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.