title: 23Na NMR study of DNA thermal transconformation in presence of cysteamine radioprotector.
abstract: DNA thermal transconformation is studied in absence and in presence of the cysteamine radioprotector, by observing the delta nu 1/2 variation of 23Na NMR peaks. The sodium state (Free or Bound) is discussed with the help of a two states model with RF and RB relaxation rates. The delta nu 1/2 behaviour during the DNA transconformation shows clearly the electrostatic interaction with cysteamine which is accompanied by an Na+ ejection out of phosphate sites. The temperature dependence of delta nu 1/2 in all cases leads to the conclusion that RBc (the average relaxation rate of sodium nuclei that remain bound in the coil state of DNA) tends to zero.
authors.affiliation: University of Nice, Biophysics Laboratory, Parc Valrose, France.
authors.forename: J
authors.initials: J
authors.lastname: Lematre
authors.forename: G
authors.initials: G
authors.lastname: Mallet
authors.forename: D
authors.initials: D
authors.lastname: Vasilescu
mesh_terms: D003543:Cysteamine / Q000494:pharmacology*; D004247:DNA / Q000187:drug effects; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008433:Mathematics; D008962:Models, Theoretical; D009691:Nucleic Acid Denaturation; D011837:Radiation-Protective Agents; D012964:Sodium; D013816:Thermodynamics
chemical_list: D011837:Radiation-Protective Agents; D003543:Cysteamine; D004247:DNA; D012964:Sodium