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-adenosylmethionine 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.
DNA binding and methyl transfer catalysed by mouse DNA methyltransferase / Reale, Anna; H., Lindsay; H. P., Saluz; S., Pradhan; R. L. P., Adams; J. P., Jost; Strom, Roberto. - In: BIOCHEMICAL JOURNAL. - ISSN 0264-6021. - STAMPA. - 312:3(1995), pp. 855-861.
DNA binding and methyl transfer catalysed by mouse DNA methyltransferase
REALE, Anna;STROM, Roberto
1995
Abstract
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-adenosylmethionine 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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.