title: DNA conformational equilibrium in the presence of Zn2+ ions in neutral and alkaline solutions.
abstract: Effect of Zn(2+) ions on DNA transition from B-form to a metallized form (m-DNA) in Tris and tetraborate buffers at pH 8.5 has been studied by visible and differential UV-spectroscopy and by thermal denaturation. The results have been compared to those obtained at pH 6.5 in cacodylate buffer. It was found that in alkaline solutions Zn(2+) ions induced a hypochromicity of the DNA absorption in the whole spectral range monitored, which was attributed to DNA transition from B- to the m-form. Complete metallization occurred only upon heating the DNA solutions containing more than ~2×10(-4) M of Zn(2+) ions. Phase diagrams of the DNA-zinc complexes at pH 6.5 and 8.5 have been obtained for the first time. The m-DNA form showed higher thermal stability compared to B-DNA.
authors: B.I. Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, 47 Lenin Avenue, Kharkov 61103, Ukraine. sorokin@ilt.kharkov.ua
authors: V A
authors: VA
authors: Sorokin
authors: V A
authors: VA
authors: Valeev
authors: E L
authors: EL
authors: Usenko
authors: V V
authors: VV
authors: Andrushchenko
mesh_terms: D000042:Absorption; D000818:Animals; D004247:DNA / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D009690:Nucleic Acid Conformation / Q000187:drug effects*; D012996:Solutions; D044366:Transition Temperature; D015032:Zinc / Q000494:pharmacology*
chemical_list: D012996:Solutions; D004247:DNA; D015032:Zinc