Bleomycin interactions with DNA. Studies on the role of the C-terminal cationic group of bleomycin A2 in association with and degradation of DNA.
The role of the cationic dimethylsulfonium group of bleomycin A2 in the binding of the drug to poly(dA-dT) has been investigated by proton NMR studies on the S-demethylated derivative. In contrast to the parent drug, the demethyl congener shows no intercalation of the aromatic bithiazole group which is adjacent to the former cationic group. However, chemical studies show that the demethyl derivative retains the capability to degrade DNA in the presence of iron(II), albeit at a reduced rate and to a lesser extent than the intact bleomycin A2. Thus, the cationic group is necessary for the intercalation of the bithiazole portion of the drug molecule; however, intercalation is not essential for the degradation of DNA.
D000818:Animals; D001761:Bleomycin / Q000378:metabolism*; D002417:Cattle; D055598:Chemical Phenomena; D002621:Chemistry; D004247:DNA / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D011067:Poly dA-dT / Q000378:metabolism; D013861:Thiocyanates
D013861:Thiocyanates; D001761:Bleomycin; D011067:Poly dA-dT; C024553:sodium thiocyanate; D004247:DNA