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Ebbe Nordlander. Portrait.

Ebbe Nordlander

Professor

Ebbe Nordlander. Portrait.

Synthesis, structure and interactions with DNA of novel tetranuclear, [Mn-4(II/II/II/IV)] mixed valence complexes

Author

  • Anastasia Dimitrakopoulou
  • Catherine Dendrinou-Samara
  • Anastasia A Pantazaki
  • Maria Alexiou
  • Ebbe Nordlander
  • Dimitris P Kessissglou

Summary, in English

Reaction of Mn(II) with phenoxyalkanoic acids and di-2-pyridyl ketone oxime (Hpko) leads to neutral tetranuclear complexes of the general formula Mn-4(O)(pko)(4)(phenoxyalkanoato)(4) (phenoxyalkanoic acids: H-mcpa = 2-methyl-4-chloro-phenoxy-acetic acid, H-2,4,5-T = 2,4.5-trichloro-phenoxy-acetic acid or H3,4-D = 3,4-dichloro-phenoxy-acetic acid). The compounds were synthesized by adding di2-pyridyl ketone oxime to MnCl2 in the presence of the sodium salts of the alkanoic acids in methanol. The crystal structure of Mn-4(II/II/ II/IV)(O)(pko)4(()2,4,5-T)(4) . 2.5CH(3)OH . 0.25H(2)O 1 shows that the complex consists of a [Mn-4( mu(4)-O)](8+) core with a Mn(IV) and 3 Mn(II) ions in octahedral environment and a mu(4)-O atom bridging the four manganese ions. Spectroscopic studies of the interaction of these tetranuclear clusters with DNA showed that these compounds bind to dsDNA. The binding strength of the Mn-4(II/II/II/ IV)(O)(pko)(4)(2,4,5-T)(4) complex for calf thymus DNA is equal to 1.1 X 10(4) M-1. Among the deoxyribonucleotides they bind preferentially to deoxyguanylic acid (dGMP). Competitive studies with ethidium bromide (EthBr) showed that the Mn-4(II/II/II/ IV)(O)(pko)(4)(2,4,.5-T)(4) complex exhibited the ability to displace the DNA-bound EthBr indicating that the complex binds to DNA via intercalation in strong competition with EthBr for the intercalative binding site. Additionally, DNA electrophoretic mobility experiments showed that all three complexes, at low cluster concentration, are obviously capable of binding to pDNA causing its cleavage (relaxation) at physiological pH and temperature. At higher cluster concentration, catenated dimer forms of pDNA was formed.

Department/s

  • Chemical Physics

Publishing year

2008

Language

English

Pages

618-628

Publication/Series

Journal of Inorganic Biochemistry

Volume

102

Issue

4

Document type

Journal article

Publisher

Elsevier

Topic

  • Biological Sciences

Keywords

  • phenoxyalkanoic acids
  • manganese complexes
  • mixed valence
  • DNA
  • interaction

Status

Published

ISBN/ISSN/Other

  • ISSN: 1873-3344