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Updated: May 27, 2025

Author Spotlight: Exploring Intrinsically Disordered Protein Dynamics Through NMR Relaxation Experiments
Published on: November 1, 2024
Anisotropic Dynamics of Protein Side Chain NH2 Groups Revealed through Analysis of 2H and 15N NMR Relaxation Rates
Xi Wang1, Binhan Yu1, Tianzhi Wang1
1Department of Biochemistry & Molecular Biology, Sealy Center for Structural Biology & Molecular Biophysics, University of Texas Medical Branch, Galveston, Texas 77555-1068, United States.
Abstract:
Although nuclear magnetic resonance (NMR) spectroscopy is powerful for protein dynamics investigations, the anisotropy of internal motions has been difficult to analyze with NMR. In principle, NMR order parameters for multiple bond vectors fixed on the same plane can reveal the anisotropy of internal motions. We investigated the anisotropic dynamics of protein asparagine (Asn) and glutamine (Gln) side chain NH2 groups using 2H and 15N NMR relaxation rates. Hindered rotations about the C-N bond causing chemical exchange between the two hydrogens of Asn/Gln NH2 groups are far slower than 2H relaxation. Using the 2H and 15N relaxation data at two magnetic fields, we determined two order parameters and 2H quadrupolar coupling constants for each NH2 group of ubiquitin. Our data clearly illuminate the heterogeneous dynamic properties of the protein side chain NH2 groups with different degrees of the motional anisotropy, which depends strongly on the local environment.
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