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1710242 
Journal Article 
DNA damage from sulfite autoxidation catalyzed by a nickel(II) peptide 
Muller, JG; Hickerson, RP; Perez, RJ; Burrows, CJ 
1997 
Yes 
Journal of the American Chemical Society
ISSN: 0002-7863
EISSN: 1520-5126 
119 
7 
1501-1506 
WOS:A1997WJ09700001 
Guanine-specific modification of both single- and double-stranded oligodeoxynucleotides via the autoxidation of sulfite is shown to be catalyzed by [NiCR](2+) (where CR = 2,12-dimethyl-3,7,11,17-tetraazabicyclo[11.3.1]heptadeca-1(17),2,11,13,15-pentaene) and [NiKGH-NH2](+) (where KGH = lysylglycylhistidine). In the latter case, the nickel complex is proposed to act as a catalyst in three separate steps of sulfur oxide chemistry. Oxidative damage of guanines led to strand scission after piperidine treatment. The observed reactivity represents the first demonstration of DNA damage by sulfite and nickel(IT) complexes. Importantly, these reactions were conducted using sulfite concentrations relevant to levels known to be cytotoxic. Mechanistic studies suggest the importance of both monoperoxysulfate and sulfate radical anion in the observed DNA damage. Evidence for formation of guanine radical cation as the initial product of DNA oxidation was found by comparison of the sequence dependence of guanine reactivity in a duplex restriction fragment. These studies underscore a role for sulfite in nickel toxicity and suggest a new method of site-specific oxidation with bioconjugates using sulfite rather than highly reactive oxidants such as monoperoxysulfate.