1. Spectroscopic studies of conformational transitions in double stranded DNAs in the presence of carcinogenic nickel compounds and an antitumoral drug (SOAZ).
- Author
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Liquier J, Bourtayre P, Pizzorni L, Sournies F, Labarre JF, and Taillandier E
- Subjects
- Circular Dichroism, Polydeoxyribonucleotides, Spectrophotometry, Ultraviolet, Antineoplastic Agents pharmacology, Azirines pharmacology, Carcinogens, DNA, Nickel toxicity, Nucleic Acid Conformation
- Abstract
The influence of an antitumoral drug, the pentaziridinocyclodiphosphatiazene (SOAZ), on the right----left-handed helix conformational transition of Poly (dG-dC). Poly (dG-dC) induced by carcinogenic or mutagenic Nickel compounds has been studied by ultraviolet absorbance and circular dichroïsm measurements. The B----Z transition of the polynucleotide is induced in two steps, in a similar way whatever the origin of the Nickel ions (NiCl2, NiSO4, Ni3S2, NiCO3). The midpoint of the second step (right----left-transition) is located around 0.4 mM Ni2+. The addition of SOAZ to the Poly (dG-dC). Poly (dG-dC) modifies this transition which is shifted to 2 mM Ni2+ for a 1 SOAZ/10 DNA phosphates ratio. The right-handed helix is stabilized and for a 1.5 SOAZ/phosphate ratio no B----Z transition is observed even for a tenfold amount of added Nickel (4 mM Ni2+). The addition of SOAZ to the DNA initially converted to a Z conformation by the presence of Nickel inhibits the return to the B form.
- Published
- 1984