N Chemical Shift Tensor Magnitude and Orientation in the Molecular Frame of Uracil Determined via MAS NMR |
| |
Authors: | Jrg Leppert Bert Heise Ramadurai Ramachandran |
| |
Institution: | Abteilung Molekulare Biophysik/NMR Spektroskopie, Institut für Molekulare Biotechnologie, D-07745, Jena, Germany |
| |
Abstract: | The potential of heteronuclear MAS NMR spectroscopy for the characterization of 15N chemical shift (CS) tensors in multiply labeled systems has been illustrated, in one of the first studies of this type, by a measurement of the chemical shift tensor magnitude and orientation in the molecular frame for the two 15N sites of uracil. Employing polycrystalline samples of 15N2 and 2-13C,15N2-labeled uracil, we have measured, via 15N–13C REDOR and 15N–1H dipolar-shift experiments, the polar and azimuthal angles (θ, ψ) of orientation of the 15N–13C and 15N–1H dipolar vectors in the 15N CS tensor frame. The (θNC, ψNC) angles are determined to be (92 ± 10°, 100 ± 5°) and (132 ± 3°, 88 ± 10°) for the N1 and N3 sites, respectively. Similarly, (θNH, ψNH) are found to be (15 ± 5°, −80 ± 10°) and (15 ± 5°, 90 ± 10°) for the N1 and N3 sites, respectively. These results obtained based only on MAS NMR measurements have been compared with the data reported in the literature. |
| |
Keywords: | chemical shift tensors dipolar couplings MAS solid-state NMR REDOR |
本文献已被 ScienceDirect 等数据库收录! |
|