ALLOSTERIC AND CATALYTIC BINDING OF S-ADENOSYLMETHIONINE TO ESCHERICHIA-COLI DNA ADENINE METHYLTRANSFERASE MONITORED BY H-3 NMR

Adenine methylation of GATC sequences in DNA is carried out by the DNA adenine methyltransferase with the methyl group source being the cofactor S-adenosylmethionine. We report H-3 NMR studies on the interaction of DNA adenine methyltransferase with S-adenosylmethionine and the reaction when the ternary complex is formed with an oligonucleotide containing a GATC site. The methylation reaction was also studied in the presence of a competitive inhibitor and this showed two successive stages involved in the methylation and two sites of binding for S-adenosylmethionine.