Acid-base, coordination and oxidative properties of systems containing ATP, L-histidine and Ni(II) ions.

Potentiometric measurements of ATP-His system proved an existence of five adducts in the solution with stoichiometries ranging from H(5)(ATP)(His) to H(ATP)(His)(4-). Their formation is a consequence of electrostatic interactions only. In the ternary Ni(II)-ATP-His system, two complex species NiH(ATP)(His)(2-) and Ni(ATP)(His)(3-), were found. In the former, stacking interaction between the aromatic moiety of ATP and the imidazole ring of l-histidine is crucial to the adduct stability. All studied systems are able to generate single strand lesions of plasmid DNA in the presence of hydrogen peroxide. However, only binary systems produce linear form of DNA, which is a consequence of the accumulation of the single-stranded breaks.