Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5420919 | Solid State Nuclear Magnetic Resonance | 2007 | 10 Pages |
Abstract
We demonstrate that the backbone torsion psi angle of a uniformly labeled residue can be determined accurately by correlating the chemical shift anisotropy of the carbonyl carbon and the 13C-1H heteronuclear dipole-dipole interaction of the alpha carbon. To obtain the highest sensitivity for the psi angle determination, the following conditions are desired: (i) the recoupling pulse sequences for the CSA and the heteronuclear dipolar interactions are gamma encoded, in which the spatial parts of m=2 are selected; (ii) the homonuclear polarization transfer is based on the scalar spin-spin coupling. Experimental data were obtained for [U-13C, 15N]-alanine and N-acetyl-[U-13C, 15N]-d,l-valine under magic-angle spinning at 25Â kHz. Only three data points are required for the measurements and the dihedral angles determined are in excellent agreement with the diffraction data.
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Authors
Yun Mou, Tim W.T. Tsai, Jerry C.C. Chan,