title: The dynamics of 57Fe nuclei in Fe(II)-DNA and [Fe(II)(1-methyl-2-mercaptoimidazole)2]-DNA condensates.
abstract: Alcoholic solutions of FeCl(2) and Fe(II)(Hmmi)(2)Cl(2) (Hmmi=1-methyl-2-mercaptoimidazole) induce calf thymus DNA condensation from aqueous solutions buffered at pH 7.4. A 1:1 Fe(II)-(DNA monomer) stoichiometry is assumed. The (57)Fe Mössbauer hyperfine parameters suggest an octahedral coordination environment, severely distorted, in both Fe(II)-(DNA monomer) and [Fe(II)(Hmmi)(2)]-(DNA monomer) condensates. The dynamic properties of iron nuclei in freeze-dried samples were investigated by means of variable temperature (57)Fe Mössbauer spectroscopy. Mean square displacements, <x(2)>(T), were calculated, such as the effective vibrating mass and the Mössbauer lattice temperature of the solids. <x(2)> increases linearly with the temperature in the whole temperature range explored; the absolute values are typical for lattice or solid-state vibrations. Very similar values for the effective vibrating masses were extracted, suggesting comparable covalency of the bonding interaction between the metal atom and its ligands, while the Mössbauer lattice temperatures show a softening of the lattice for [Fe(II)(Hmmi)(2)]-(DNA monomer) with respect to Fe(II)-(DNA monomer) condensate.
authors.affiliation: Dipartimento di Chimica Inorganica e Analitica Stanislao Cannizzaro, Università di Palermo, Viale delle Scienze-Parco d'Orleans II, I-90128, Palermo, Italy.
authors.forename: Arturo
authors.initials: A
authors.lastname: Silvestri
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Ruisi
authors.forename: Maria Assunta
authors.initials: MA
authors.lastname: Girasolo
mesh_terms: D000818:Animals; D004247:DNA / Q000737:chemistry*; D005296:Ferrous Compounds / Q000737:chemistry*; D008713:Methimazole / Q000737:chemistry; D015394:Molecular Structure; D015204:Spectroscopy, Mossbauer; D014732:Vibration
chemical_list: D005296:Ferrous Compounds; D008713:Methimazole; D004247:DNA; C427203:calf thymus DNA