Effect of S-adenosyl-L-methionine and its analogues on site-specific binding of DNA-(adenine-N-6)-methyltransferase of T4 phage with the oligonucleotide substrate

Using fluorescence of 2-aminopurine substituted oligonucleotide duplexes, " flipping" of the target base in the process of interaction of T4 DNA-(adeni ne N-6)-methyltransferase (EC 2.1.1.72) with the substrate double stranded DNA was revealed. It was shown that S-adenosyl-L-methionine, the methyl gro up donor, induces the reorientation of the enzyme relative to the asymmetri cally modified recognition site.