Magnitudes and Orientations of the 15N Chemical Shift Tensor of [1-15N]-2′-Deoxyguanosine Determined on a Polycrystalline Sample by Two-Dimensional Solid-State NMR Spectroscopy

Abstract

The magnitudes and orientations of the 15N chemical shift tensor of [1-15N]-2′-deoxyguanosine were determined from a polycrystalline sample using the two-dimensional PISEMA experiment. The magnitudes of the principal values of the 15N chemical shift tensor of the N1 nitrogen of [1-15N]-2′-deoxyguanosine were found to be σ11 = 54 ppm, σ22 = 148 ppm, and σ33 = 201 ppm with respect to (15NH4)2SO4 in aqueous solution. Comparisons of experimental and simulated two-dimensional powder pattern spectra show that σ33N is approximately collinear with the N-H bond. The tensor orientation of σ33N for N1 of [1-15N]-2′-deoxyguanosine is similar to the values obtained for the side chain residues of 15N∈1-tryptophan and 15Nπ-histidine even though the magnitudes differ significantly. © 1999 Academic Press.