title: Stabilization of (dG-dC)n.(dG-dC)n in the Z conformation by a crosslinking reaction.
abstract: (dG-dC)n.(dG-dC) was converted to the Z conformer by heating in the presence of Mn++n. Reaction of this preparation with the crosslinking reagent, DL-diepoxybutane (DEB), stabilized this conformer so that it retained its structure even when returned to conditions that favored reversion to the B conformation. Treatment of the crosslinked Z conformer with periodate caused scission of the crosslink, allowing reversion to the B conformer. Reaction of (dG-dC)n.(dG-dC)n in the B conformation with DEB did not prevent conversion to the Z conformer in 4M NaC1; dialysis of the high salt solution against low ionic strength buffer allowed return to the B conformer. The Z in equilibrium B transitions were followed by circular dichroism studies and immunochemical procedures. The results suggest the feasibility of stabilizing Z sequences of DNA in chromatin by crosslinking, so that they could then be identified after DNA isolation.
mesh_terms: D002942:Circular Dichroism; D004355:Drug Stability; D004852:Epoxy Compounds; D004988:Ethers, Cyclic; D007700:Kinetics; D008345:Manganese; D009153:Mutagens; D009690:Nucleic Acid Conformation; D011089:Polydeoxyribonucleotides
chemical_list: D004852:Epoxy Compounds; D004988:Ethers, Cyclic; D009153:Mutagens; D011089:Polydeoxyribonucleotides; C019530:poly(dC-dG); D008345:Manganese; C007366:diepoxybutane