A study of the binding of manganese (II) with the sodium salts of nucleosides in aqueous solutions by the13C NMR method

Abstract

The binding of manganese(II) with nucleosides — adenosine (A), guanosine (G), cytidine (C), and uridine (U) — in an alkaline D2O solution has been investigated by the13C NMR method. It has been established that the structure of the paramagnetic Mn(II)—nucleoside complexes differs substantially in neutral and in alkaline media. The broadening of the resonance lines (C-2′, C-3′ > C-1′, C-4′ > C-5′) shows the localization of the Mn(II) in the C-2′ and C-3′ hydroxyls of the ribose in an alkaline medium. It has been shown for the case of U that the degree of complex-formation depends on the pH of the solution. It is assumed that the nucleoside forms intramolecular complexes (I) with Mn(OH)2.