title: Diepoxybutane forms a monoadduct with B-form (dG-dC)n.(dG-dC)n and a crosslinked diadduct with the left-handed Z-form.
abstract: The characteristics of the reactions of DL-diepoxybutane (DEB) with (dG-dC)n.(dG-dC)n in the right-handed B-form or the left-handed Z-form were investigated. DEB does react with right-handed B-DNA since less salt is required to convert the modified B-form to Z-form than for the unmodified DNA. However, the product appears to be a monoadduct rather than the crosslinked diadduct formed with the Z-form. The modified B-form can be isolated, converted to a Z-form with l mM MnCl2, and then this activated complex further reacts intramolecularly to give the crosslinked Z-product. This modified Z-form cannot be reverted to the B-form unless the crosslink is cleaved with periodate. Only MnCl2, and to a lesser extent ZnCl2, was effective in facilitating the intramolecular conversion of the B-DNA monoadduct to the Z-DNA diadduct; lmM MgCl2 and 4M NaCl were ineffective suggesting that somewhat different types of modified left-handed conformations were generated by the different salts. DEB also cleaves DNA under our reaction conditions thus precluding studies with supercoiled recombinant plasmids harboring segments that adopt Z-structures.
authors.forename: D S
authors.initials: DS
authors.lastname: Kang
authors.forename: S C
authors.initials: SC
authors.lastname: Harvey
authors.forename: R D
authors.initials: RD
authors.lastname: Wells
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D002712:Chlorides; D002942:Circular Dichroism; D003432:Cross-Linking Reagents; D004852:Epoxy Compounds / Q000494:pharmacology*; D004988:Ethers, Cyclic / Q000494:pharmacology*; D007700:Kinetics; D008345:Manganese / Q000494:pharmacology; D017895:Manganese Compounds; D009690:Nucleic Acid Conformation / Q000187:drug effects; D010504:Periodic Acid / Q000494:pharmacology; D011089:Polydeoxyribonucleotides; D012965:Sodium Chloride / Q000494:pharmacology; D015032:Zinc / Q000494:pharmacology; D017967:Zinc Compounds
chemical_list: D002712:Chlorides; D003432:Cross-Linking Reagents; D004852:Epoxy Compounds; D004988:Ethers, Cyclic; D017895:Manganese Compounds; D011089:Polydeoxyribonucleotides; D017967:Zinc Compounds; D010504:Periodic Acid; C019530:poly(dC-dG); D008345:Manganese; D012965:Sodium Chloride; C007366:diepoxybutane; C016837:zinc chloride; C009288:metaperiodate; D015032:Zinc; C025340:manganese chloride