STOICHIOMETRY OF PHAGE-T4 DAM DNA(ADENINE-N6)-METHYLTRANSFERASE BINDING WITH OLIGONUCLEOTIDE SUBSTRATES

Phage T4 Dam DNA methyltransferase recognizes the GATC site and methyl ates the adenine N6. The stoichiometry of its complex with the substra te was assessed by gel filtration and sucrose gradient ultracentrifuga tion. The results obtained by both methods indicate that two enzyme su bunits bind with 32- and 20-bp DNA duplexes.