Studies of DNA damage induced by sulfite autoxidation in the presence of Cu(II)/tetraglycine complexes. Effect synergistic of Ni(II), Co(II) and Mn(II). / Estudos de lesão ao DNA promovida pela autoxidação de S(IV) na presença de complexos de Cu(III)/tetraglicina. Efeito sinérgico de Ni(II), Co(II) e Mn(II)

AUTOR(ES)

Ruben Gregorio Moreno Moreno

DATA DE PUBLICAÇÃO

2005

RESUMO

The present work presents studies related to biomolecules damage (DNA and 2-deoxyguanosine) induced by Cu(III)/tetraglycine (Cu(III)/G4), oxysulfur radicals (SO3·-, SO4·-, SO5·-) and HSO5-, species generated during S(IV) autoxidation in the presence of Cu(II)/G4 or Cu(II) (absence of tetraglycine) and trace level of a second metal ion (Ni(II), Co(II) or Mn(II)). The formation of SO3·- and HO· radicals was detected by electronic paramagnetic resonance technique (EPR). Spectrophotometric and circular dichroism techniques were used to evaluate the Cu(III)/G4 formation in different experimental conditions, in the presence and the absence of S(IV), and the interaction of copper (II)/(III) complexes and DNA molecule. The effectiveness of Cu(III) formation depends on the acidity, S(IV) concentration, and buffers used. The damage on pUC 19 plasmid DNA was verified by agarose gel electrophoresis. The extent on the DNA damage was related to acidity, S(IV) concentration, incubation time and to the presence of a second metal ion. Using the high performance liquid chromatography technique (HPLC) it was possible to study the oxidation of 2-deoxyguanosine to 8-oxo-7,8-dihydro-2-deoxyguanosine in the presence of strong oxidants generated during the S(IV) autoxidation catalyzed by Cu(II)/G4. A comparative study of the effect of several metal ions showed the synergism of Cu(II) and traces of a second metal ion (Ni(II), Co(II) or Mn(II), as tetraglycine complexes or not).

ASSUNTO(S)

cobre dna complexos metálicos oxy sulfur radicals free radicals copper sulfite tetraglicina dna sulfito Óxidos de enxofre metals complexes tetraglycine biomolecules damage radicais livre lesão em biomoléculas

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