Protecting against Bgl II digestion - (Mar/21/2007 )
The Bgl II recognition sequence AGATCT contains a perfect Dam methylation site (GATC) but the enzyme itself is not sensitive to methylation. My question is how does the organism that makes Bgl II protect its genome from self-digestion? As far as I know methylation usually prevents self-digestion, but this obviously isn't true in this case.
BglII methylase adds a methyl group to the N4 site of the cytosine in the AGATCT sequence. The BglII enzyme is insensitive to the normal m6 methylation of the adenines, which is type of methylation performed by the dam gene. See the rebase entry here:
Different methylation. Cheers Phage