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Updated: Aug 4, 2025

Atomic Scale Structural Studies of Macromolecular Assemblies by Solid-state Nuclear Magnetic Resonance Spectroscopy
Published on: September 17, 2017
Determination of the relative orientation between 15N-1H dipolar coupling and 1H chemical shift anisotropy tensors
Neelam Sehrawat1, Ekta Nehra1, Ketan Kumar Rohilla1
1Indian Institute of Technology (IIT) Ropar, Rupnagar, Punjab 140001, India.
Abstract:
In this work, we have proposed a proton-detected three-dimensional (3D) 15N-1H dipolar coupling (DIP)/1H chemical shift anisotropy (CSA)/1H chemical shift (CS) correlation experiment to measure the relative orientation between the 15N-1H dipolar coupling and the 1H CSA tensors under fast magic angle spinning (MAS) solid-state NMR. In the 3D correlation experiment, the 15N-1H dipolar coupling and 1H CSA tensors are recoupled using our recently developed windowless C-symmetry-based C331-ROCSA (recoupling of chemical shift anisotropy) DIPSHIFT and C331-ROCSA pulse-based methods, respectively. The 2D 15N-1H DIP/1H CSA powder lineshapes extracted using the proposed 3D correlation method are shown to be sensitive to the sign and asymmetry of the 1H CSA tensor, a feature that allows the determination of the relative orientation between the two correlating tensors with improved accuracy. The experimental method developed in this study is demonstrated on a powdered U-15N L-Histidine.HCl·H2O sample.
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