Histamine modified 2'-deoxyriboadenosine--potential copper binding site in DNAzymes.

Copper(II) complexes of histamine modified 2'-deoxyriboadenosine (N-[(9-beta-D-2'-deoxyribofuranosylpurin-6-yl)-carbamoyl]histamine) ligand were studied by potentiometric, UV-visible and EPR techniques. The imidazole residue of the ligand was described as the main binding site forming mono-, bis-(ligand) and dimer complexes, but the interactions between adenosine nitrogen N(1) and carbamoyl nitrogen atoms and the copper(II) ion also were detected. This is the first report evaluating the coordinating ability of such a modified adenosine ligand towards copper(II) ion. Our findings suggest that histamine modified 2'-deoxyriboadenosine could chelate efficiently copper(II) ions if it were incorporated into DNAzyme sequence.