A methylase that recognizes the double-stranded sequence 5'-CTAT-3' and methylates A-3 on one strand; probably responsible for all of the methylation on this site in the genome. a 2'-deoxyadenosine in DNA + S-adenosyl-L-methionine = an N(6)-methyl-2'-deoxyadenosine in DNA + H(+) + S-adenosyl-L-homocysteine Detected after 6 and 96 hours growth, there are fewer copies at 96 hours (at protein level). Essential it cannot be disrupted. Belongs to the N(4)/N(6)-methyltransferase family.