title: Enzymatic methylation of chemically alkylated DNA and poly(dG-dC) X poly(dG-dC) in B and Z forms.
abstract: The enzymatic methylation of chemically alkylated DNA and of poly(dG-dC) X poly(dG-dC) by beef brain DNA(cytosine-5-)-methyltransferase have been tested. The alkylation by dimethylsulfate, which yields mostly 7 methylguanine (m7G) and 3 methyladenine (m3A) do not affect the enzymatic methylation. The dimethylsulfate alkylated poly(dG-dC) X poly(dG-dC) converted into the Z-form in the presence of MgCl2, is just as well methylated as the native or the alkylated polynucleotide in the B-form. The alkylation of DNA or of poly(dG-dC) X poly(dG-dC) by methylnitrosourea yields, in addition to the above base modifications described for dimethylsulfate, methylphosphotriesters and O6-methylguanine. The enzymatic methylation of these substrates modified by methylnitrosourea is decreased. This decrease is proportional to the extent of the chemical alkylation of the substrate.
mesh_terms: D000478:Alkylation; D000818:Animals; D002417:Cattle; D002645:Chickens; D004247:DNA / Q000378:metabolism*; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000378:metabolism; D008745:Methylation; D008770:Methylnitrosourea / Q000494:pharmacology; D009690:Nucleic Acid Conformation / Q000187:drug effects; D011089:Polydeoxyribonucleotides / Q000378:metabolism*; D013463:Sulfuric Acid Esters / Q000494:pharmacology
chemical_list: D011089:Polydeoxyribonucleotides; D013463:Sulfuric Acid Esters; C019530:poly(dC-dG); D008770:Methylnitrosourea; D004247:DNA; D004248:DNA (Cytosine-5-)-Methyltransferases; C007482:dimethyl sulfate