The subtype gamma methyltransferase (M) subunit of a type I restriction enzyme. The M and S subunits together form a methyltransferase (MTase) that probably methylates A-2 on the top strand and A-3 on the bottom strand of the sequence 5'-GAN(7)TAY-3'. As the bacterial DNA is methylated on this sequence and this is the only type I methylase in the genome, it is probably responsible for all of the methylation on this site in the genome. The R subunit has multiple frameshifts and is probably not expressed in this bacteria. a 2'-deoxyadenosine in DNA + S-adenosyl-L-methionine = an N(6)-methyl-2'-deoxyadenosine in DNA + H(+) + S-adenosyl-L-homocysteine The methyltransferase is composed of M and S polypeptides. Detected at low levels after 6 and 96 hours growth, there are fewer copies at 96 hours (at protein level). Belongs to the N(4)/N(6)-methyltransferase family.