N 4-Methylcytosine

In prokaryotic DNA the major methylated bases are N6-methyladenine (mA) and to a lesser extent N4-methylcytosine. Methylation in bacteria occurs at specific sites. In E. coli, methylation of A residues in the sequence 5´-GATC-3´ is involved in mismatch error correction, and it plays a role in controlling initiation of DNA replication. Methylation at other sites protects DNA against cleavage by restriction endonucleases (described here).

See also: DNA Methylation, Prokaryotic Mismatch Repair, Initiation of DNA Replication

INTERNET LINK: The Effect of Site-Specific Methylation on Promega Restriction Enzymes