Magnetic resonance reinvestigation of MnII–5′ ATP equilibria in solution

Abstract

The Mn^II–5′ ATP system in aqueous solution has been reinvestigated in order to understand the complexation mechanisms. Lineshape e.s.r. analysis, linewidth variation, water-proton nuclear relaxation rates dependent on molar ratios, temperature and pH provide information on dynamics of the metal–nucleotide complex. The combined use of e.s.r. and n.m.r. techniques follows the equilibria between various Mn^II–5′ ATP inner-and outer-sphere complexes in solution. A chemical equilibrium taking into account the presence of Mn(ATP)_x species at high pH and 5′-ATP concentrations is proposed.