INTERACTION OF METAL-IONS WITH NUCLEIC-ACIDS - INTERACTION OF COPPER(II) WITH INOSINE AND ITS DERIVATIVES

Abstract

The interaction of Cu(II) with inosine, 2''-deoxyinosine, 1-methylinosine, 7-deazainosine, 6-methoxypurine riboside and IMP was examined. Cu binds with the purine base of the nucleosides, and in IMP also with the phosphate group. No interaction with ribose hydroxyl groups was observed. In a non-aqueous medium, the main site of Cu binding is N-7 of inosine and 1-methylinosine, and additionally N-1 in 6-methoxypurine riboside. In an aqueous medium, coordination of Cu with N-1 and N-7 of inosine and IMP is pH-dependent. Formation of either a 5-membered Cu chelate with N-7 and O at C-6, or a 4-membered chelate of the type C(6).sbd.O.sbd.Cu.sbd.N(1), is rather unlikely. The crystalline Cu-IMP complex [Cu(C10H11O8N4P).cntdot.(H2O)] probably contains 2 Cu atoms coordinated in different manner. The phosphate group and N-7, but not the carbonyl O, participate in the complex formation.