Anisotropic Dynamics of Protein Side Chain NH<sub>2</sub> Groups Revealed through Analysis of <sup>2</sup>H and <sup>15</sup>N NMR Relaxation Rates
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 NH<sub>2</sub> groups using <sup>2</sup>H and <sup>15</sup>N NMR relaxation rates. Hindered rotations about the C-N bond causing chemical exchange between the two hydrogens of Asn/Gln NH<sub>2</sub> groups are far slower than <sup>2</sup>H relaxation. Using the <sup>2</sup>H and <sup>15</sup>N relaxation data at two magnetic fields, we determined two order parameters and <sup>2</sup>H quadrupolar coupling constants for each NH<sub>2</sub> group of ubiquitin. Our data clearly illuminate the heterogeneous dynamic properties of the protein side chain NH<sub>2</sub> groups with different degrees of the motional anisotropy, which depends strongly on the local environment.
Authors
- Junji Iwahara (ORCID: https://orcid.org/0000-0003-4732-2173)
- Binhan Yu (ORCID: https://orcid.org/0000-0002-8958-3470)
- Tianzhi Wang (ORCID: https://orcid.org/0000-0001-6838-0757)
- Xi Wang (ORCID: https://orcid.org/0000-0002-7572-6354)
Institutions
- Institute of Molecular Biology and Biophysics (RU)
- The University of Texas Medical Branch at Galveston (US)
Publication Details
- Journal
- The Journal of Physical Chemistry Letters
- Published
- 2025-02-21
- DOI
- https://doi.org/10.1021/acs.jpclett.4c03666
- Citations
- 2
- Primary Topic
- Protein Structure and Dynamics
- Type
- article
- Field-Weighted Citation Impact
- 1.61
Funders
- Welch Foundation
- National Institutes of Health
- National Institute of General Medical Sciences