DNA binding and methyl transfer catalysed by mouse DNA methyltransferase.
By using a purified fraction of mouse DNA methyltransferase we have shown, by gel-retardation analysis, that the enzyme forms a low-affinity complex preferentially with hemimethylated DNA; the complexes formed with unmethylated or with fully methylated DNA are of even lower affinity, and only very weak interaction occurs with DNA lacking CG dinucleotides. Interaction is inhibited by N-ethylmaleimide. Methyl transfer from S-adenosyl-methionine is associated with the release of the fully methylated product from the complex. Complexes formed with the intact enzyme are extremely large, but limited trypsin treatment allows a major complex to enter the gel. DNA binding is not inhibited by this limited proteolysis of the native enzyme.
Reale
A
A
Institute of Biomedical and Life Sciences, University of Glasgow, Scotland, U.K.
Lindsay
H
H
Saluz
H P
HP
Pradhan
S
S
Adams
R L
RL
Jost
J P
JP
Strom
R
R
D000818:Animals; D001482:Base Composition; D001667:Binding, Competitive; D004247:DNA / Q000378:metabolism*; D015254:DNA Modification Methylases / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005033:Ethylmaleimide / Q000494:pharmacology; D007700:Kinetics; D008745:Methylation; D051379:Mice; D009838:Oligodeoxyribonucleotides / Q000737:chemistry / Q000378:metabolism; D010455:Peptides / Q000378:metabolism; D012436:S-Adenosylmethionine / Q000378:metabolism; D014357:Trypsin / Q000494:pharmacology
D009838:Oligodeoxyribonucleotides; D010455:Peptides; D012436:S-Adenosylmethionine; D004247:DNA; D015254:DNA Modification Methylases; D014357:Trypsin; D005033:Ethylmaleimide