title: Specific features of Zn²⁺, Co²⁺ and Ni²⁺ ion binding to DNA in alkaline solutions.
abstract: Dependence of DNA metallization degree during B-DNA transition into the metallized (m) form on DNA concentration has been studied by visible and differential UV-spectroscopy in the presence of Zn(2+), Co(2+) and Ni(2+) ions in tetraborate buffer (pH 8.5) with and without ethidium bromide. Constants of Mt(2+) binding to double stranded DNA were calculated. The obtained binding constants corresponded to the formation of inter-strand metal bridges stabilizing m-form. Thermodynamic origin of higher efficiency of Zn(2+) ions in DNA metallization compared to Co(2+) and Ni(2+) was revealed. Increase of the DNA helix-coil transition temperature by up to 10°С upon formation of m-form in the presence of Zn(2+) ions was observed and rationalized. Furthermore, a strong cooperative decrease (up to 30°С) of the temperature of В→m transition induced by heating in the presence of Zn(2+) was found and its nature was explained.
authors: BI 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: Ya P
authors: YP
authors: Rakovsky
authors: V V
authors: VV
authors: Andrushchenko
mesh_terms: D002412:Cations / Q000737:chemistry; D003035:Cobalt / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D004996:Ethidium / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D009532:Nickel / Q000737:chemistry*; D012996:Solutions; D015032:Zinc / Q000737:chemistry*
chemical_list: D002412:Cations; D012996:Solutions; D003035:Cobalt; D009532:Nickel; D004247:DNA; D004996:Ethidium; D015032:Zinc