A calorimetric study of the Ni(II)-5' AMP system. A base-stacking stabilization.
The thermodynamic parameters of the interaction between Ni(II) (M) and 5'-AMP in aqueous solution were determined calorimetrically (I = 0.1 tetramethylammonium bromide, 25 degrees C) at physiological pH. The experimental conditions were carefully selected to avoid the polynuclear complex formation. From the Ni(5'AMP)-complex-formation constant (logK1 = 2.55), the Ni(5'AMP)2(2-)-complex-formation constant and the Ni(5'AMP) (ML) and Ni(5'AMP)2(2-) (ML2) complex-formation enthalpies were determined (logK2 = 2.34, delta H1 = -10.0 kJ/mol and delta H2 = 21.6 kJ/mol). These results confirm the formation of the ML2 complex in solution and agree very well with the hypothesis of the 'stacking' between the purine rings, promoted for metal ions.
Herrero
L A
LA
Department of Chemistry, Universitat de les Illes Balears, Palma de Mallorca, Spain.
Calafat
A M
AM
Terrón
A
A
D000249:Adenosine Monophosphate / Q000737:chemistry*; D002151:Calorimetry; D002413:Cations, Divalent; D008433:Mathematics; D009532:Nickel / Q000737:chemistry*; D012984:Software; D013816:Thermodynamics
D002413:Cations, Divalent; D000249:Adenosine Monophosphate; D009532:Nickel