[Effect of Ecodam DNA-methylase on single-stranded sequences and synthetic oligonucleotides].

Interaction of the Ecodam methylase with different substrates were investigated among them the double- and single-stranded DNAs and synthetic oligonucleotides containing some defects in the GATC sequence. These defects were:nick, the absence of one internucleotide phosphate of nucleotide; partially single-stranded form on the recognition site etc. It was demonstrated that the presence of both G . A-dinucleotides in the recognition site is necessary for productive enzyme-substrate interaction. The absence of T and/or C residues is less dramatic for methylase activity. The Ecodam methylase is capable to modify the single-stranded oligonucleotides by forming the double-stranded structure in the symmetric recognition sequences GATC.