Structural analysis of Cu(II) ligation to the 5'-GMP nucleotide by pulse EPR spectroscopy

Maria Grazia Santangelo, Arthur Schweiger, George Mitrikas, Bernhard Spingler, Maria Grazia Santangelo, Alfredo Medina-Molner

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Abstract

Simple copper salts are known to denature poly d(GC). On the other hand, copper complexes of substituted 1,4,7,10,13-pentaazacyclohexadecane-14,16-dione are able to convert the right-handed B form of the same DNA sequence to the corresponding left-handed Z form. A research program was started in order to understand why Cu(II) as an aquated ion melts DNA and induces the conformational change to Z-DNA in the form of an azamacrocyclic complex. In this paper, we present a continuous wave and pulse electron paramagnetic resonance study of the mononucleotide model system Cu(II)-guanosine 5'-monophosphate . Pulse EPR methods like electron-nuclear double resonance and hyperfine sublevel correlation spectroscopy provide unique information about the electronic and geometric structure of this model system through an elaborate mapping of the hyperfine and nuclear quadrupole interactions between the unpaired electron of the Cu(II) ion and the magnetic nuclei of the nucleotide ligand. It was found that the Cu(II) ion is directly bound to N7 of guanosine 5'-monophosphate and indirectly bound via a water of hydration to a phosphate group. This set of experiments opens the way to more detailed structural characterization of specifically bound metal ions in a variety of nucleic acids of biological interest, in particular to understand the role of the metal-(poly)nucleotide interaction.
Lingua originaleEnglish
pagine (da-a)767-775
Numero di pagine9
RivistaJBIC
Volume12
Stato di pubblicazionePublished - 2007

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All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Inorganic Chemistry

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Santangelo, M. G., Schweiger, A., Mitrikas, G., Spingler, B., Santangelo, M. G., & Medina-Molner, A. (2007). Structural analysis of Cu(II) ligation to the 5'-GMP nucleotide by pulse EPR spectroscopy. JBIC, 12, 767-775.