DNA damage and 2'-deoxyguanosine oxidation induced by S(IV) autoxidation catalyzed by copper(II) tetraglycine complexes: synergistic effect of a second metal ion.
S(IV) (SO(2),HSO(3)(-)andSO(3)(2-)) autoxidation catalyzed by Cu(II)/tetraglycine complexes in the presence of DNA or 2'-deoxyguanosine (dGuo) resulted in DNA strand breaks and formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo), respectively. Ni(II), Co(II) or Mn(II) (1.0x10(-4)M) complexes had much smaller effects. Cu(II)/tetraglycine (1.0x10(-4)M) in the presence of Ni(II) or Mn(II) (10(-7)-10(-6)M) and S(IV) showed remarkable synergistic effect with these metal ions producing a higher yield of 8-oxodGuo. Oxidation of dGuo and DNA damage were attributed to oxysulfur radicals formed as intermediates in S(IV) autoxidation catalyzed by transition metal ions. SO*(3)(-) and HO* radicals were detected by EPR-spin trapping experiments with DMPO (5,5-dimethyl-1-pyrroline-N-oxide).
Moreno
Ruben G M
RG
Instituto de Química, Universidade de São Paulo, CP 26077, CEP 05513-970, São Paulo, SP, Brazil.
Alipázaga
María V
MV
Gomes
Osmar F
OF
Linares
Edlaine
E
Medeiros
Marisa H G
MH
Coichev
Nina
N
D003300:Copper / Q000737:chemistry*; D004249:DNA Damage; D003849:Deoxyguanosine / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D004587:Electrophoresis, Agar Gel; D009842:Oligopeptides / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D013053:Spectrophotometry; D013458:Sulfur Dioxide / Q000737:chemistry*
D009842:Oligopeptides; D009942:Organometallic Compounds; D013458:Sulfur Dioxide; D003300:Copper; D003849:Deoxyguanosine; C046274:glycyl-glycyl-glycyl-glycine