Vibrational Analysis of Heavy Metal-Nucleotide Interactions

Abstract

The interaction of Co²⁺ and Pd²⁺ with deoxyguanosine 5'-monophosphate (dGMP) in an aqueous solution at neutral pH with cation/ dGMP molar ratios (r) 1/5 and 1 was characterized by FT-Raman spectroscopy. Spectroscopic results show the formation of several types of cationdGMP complexes. Heavy metal perturbation of the phosphodioxy band at 1091 cm^-1 is higher for Pd²⁺ than for Co²⁺. The spectral changes observed for the phosphodiester vibrations show that more than 50 % of the backbone geometry is eliminated in Co²⁺ and 100 % in case of Pd²⁺. In Co-dGMP complex, the glycosyl bond shows more flexibility, whereas in presence of Pd²⁺ ion, the guanine nucleoside exhibits both C2'-endo/anti and C3'-endo/syn conformation. Both the ions have strong affinity for the guanine base and the effect is more pronounced in the presence of Pd²⁺ ions.