A Fourier transform infrared study of the electrophilic attack at the N7-site of guanosine-5′-monophosphate

Abstract

Fourier transform infrared spectra of several N7-bound cations of guanosine-5′monophosphate disodium salt (5′-GMPNa2), such as N7-H+GMP, N7-MeGMP, and N7-MGMP, where Me = CH3+ and M = divalent metal ions, Cd, Mn, Co, Ni, Cu, Pt, and Mg, have been recorded and a correlation between the spectral changes and the nature of the electrophile (H+, CH3+, and M2+) bound has been established. Spectroscopic evidence shows that methylation of the N7-position of 5′-GMPNa2 causes larger perturbation on the guanine ring system than protonation or metalation, in the order Me+ > H+ > M2+. The effect of an N7-electrophilic attack on the vibrational frequencies of the purine, the sugar, and the phosphate group is discussed.