title: Anions or cations: who is in charge of inhibiting the nickel(II) promoted B- to Z-DNA transition?
abstract: Various weakly binding cations and anions were studied at a concentration of 10 mM to ascertain their interaction with the nickel(II) promoted B- to Z-DNA transition of poly d(GC). These salts were ranked according to the decreasing amounts of nickel needed for the B- to Z-DNA transition and provided the following order: NaCl approximately Me4NCl > LiCl >> MgCl2 > no salt > NaBF4 approximately NaNO3 approximately NaClO4. Remarkably, it was found that going from sodium nitrate to sodium chloride increased the necessary amount of nickel to induce the transition to the left-handed helix of poly d(GC) by a factor of 10. This dramatic effect cannot be explained by the binding constant of nickel(II) to chloride to form the monocationic complex. We believe that this is the first reported example of the role of chloride anions, which appear to modulate the interaction of nickel(II) ions with the polyanionic DNA.
authors.affiliation: University of Zürich, Institute of Inorganic Chemistry, Winterthurerstr 190, CH-8057 Zürich, Switzerland. spingler@aci.unizh.ch
authors.forename: Bernhard
authors.initials: B
authors.lastname: Spingler
mesh_terms: D000838:Anions; D001894:Borohydrides / Q000494:pharmacology; D002412:Cations; D004247:DNA / Q000737:chemistry*; D043542:DNA, Z-Form / Q000737:chemistry*; D018021:Lithium Chloride / Q000494:pharmacology; D015636:Magnesium Chloride / Q000494:pharmacology; D008744:Methylamines / Q000737:chemistry; D009532:Nickel / Q000737:chemistry*; D009690:Nucleic Acid Conformation / Q000187:drug effects; D009691:Nucleic Acid Denaturation / Q000187:drug effects; D011089:Polydeoxyribonucleotides / Q000737:chemistry*; D012965:Sodium Chloride / Q000494:pharmacology; D012969:Sodium Fluoride / Q000494:pharmacology
chemical_list: D000838:Anions; D001894:Borohydrides; D002412:Cations; D043542:DNA, Z-Form; D008744:Methylamines; D011089:Polydeoxyribonucleotides; D015636:Magnesium Chloride; C019530:poly(dC-dG); D012965:Sodium Chloride; D009532:Nickel; D012969:Sodium Fluoride; D004247:DNA; C027451:methylamine; D018021:Lithium Chloride