Determination of the Backbone Torsion Psi Angle by Tensor Correlation of Chemical Shift Anisotropy a

• 作 者: YunMou;TimW.T.Tsai;JerryC.C.Chan;
• 机 构: Department of Chemistry, National Taiwan University, No.1, Section 4, Roosevelt Road, Taipei, Taiwan
• 出 处: 第一届海峡两岸磁共振学术会议
• 发表日期: 2007年期

　　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 part with m =2 is 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 25 kHz.Only three data points are required for the measurements and the dihedral angles determined are in excellent agreement with the diffraction data.