N4,5-dimethylcytosine, a novel hypermodified base in DNA.
Successive enzymatic modification of DNA by two methyltransferases that recognize identical or overlapping sequences and normally target either 5- or N4-position of the same cytosine residue, can lead to the formation of a doubly methylated base--N4,5-dimethylcytosine. Implications of such enzymatic "permethylation" of cytosine on the structure and interactions of DNA are examined.
Klimasauskas
Saulius
S
Laboratory of Biological DNA Modification, Institute of Biotechnology, Graiciuno 8, LT-2028 Vilnius, Lithuania.
Gerasimaite
Ruta
R
Vilkaitis
Giedrius
G
Kulakauskas
Saulius
S
D003596:Cytosine / Q000031:analogs & derivatives / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D019175:DNA Methylation
C476816:N4,5-dimethylcytosine; D003596:Cytosine; D004247:DNA