Specific type of interactions in the quaternary system of Cu(II), adenosine 5′-triphosphate, 1,11-diamino-4,8-diazaundecane and uridine

Complexation reactions in the quaternary system Cu/ATP/3,3,3-tet/Urd have been studied. The stability constants of the complexes of the Cu(ATP)(3,3,3-tet)Hx(Urd) type have been determined by computer analysis of the potentiometric titration. On the basis of the results of spectroscopic as well as equilibrium studies, the mode of interactions has been proposed. Metal ions coordinate phosphate groups of ATP and nitrogen atoms of polyamine. It has been established that in the conditions of the complex Cu(ATP)(3,3,3-tet) formation, uridine introduced into the Cu(II)/ATP/3,3,3-tet ternary system is involved in hydrogen bonding with the endocyclic nitrogen atoms N(1) and N(7) of the ATP purine ring and formation of the adduct Cu(ATP)(3,3,3-tet)H(Urd) is observed. Introduction of metal ions into the system changes substantially the mode of interactions between complementary base pairs relative to that proposed in the Watson and Crick model.