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Updated: Jun 21, 2026
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Atomic Scale Structural Studies of Macromolecular Assemblies by Solid-state Nuclear Magnetic Resonance Spectroscopy
Published on: September 17, 2017
15N-1H scalar coupling perturbation: an additional probe for measuring structural changes due to ligand binding
Junhe Ma1, James M Gruschus, Nico Tjandra
1Laboratory of Molecular Biophysics, National Heart, Lung, and Blood Institute, National Institutes of Health, 50 South Drive, Bethesda, Maryland 20892, USA.
Journal of the American Chemical Society
|July 8, 2009
Summary
Amide scalar coupling perturbation mapping reveals structural changes near and far from ligand binding sites. This technique complements chemical shift mapping, offering insights into biomolecular interactions and allosteric effects.
Area of Science:
- Biomolecular Nuclear Magnetic Resonance (NMR) Spectroscopy
- Structural Biology
- Protein-Ligand Interactions
Background:
- Chemical shift perturbation (CSP) mapping of backbone amides is a standard technique in biomolecular NMR.
- CSP provides residue-specific data on interaction interfaces, ligand binding, and modification sites, even for challenging biomolecular samples.
- Amide (15)N-(1)H scalar coupling constants can also change upon ligand binding.
Purpose of the Study:
- To investigate the utility of amide scalar coupling constant perturbations as a complementary technique to CSP.
- To assess the information gained from scalar coupling perturbations regarding structural changes, including allosteric effects.
- To evaluate the application of this method in understanding glutamine binding protein (GlnBP) interactions.
Main Methods:
- Nuclear Magnetic Resonance (NMR) spectroscopy was used to measure chemical shift perturbations and amide (15)N-(1)H scalar coupling constants.
- The study focused on glutamine binding protein (GlnBP) and its response to ligand binding.
- Analysis involved comparing changes in scalar coupling constants with chemical shift perturbations.
Main Results:
- Significant changes in amide (15)N-(1)H scalar coupling constants were observed upon ligand binding to GlnBP, with large perturbations (>1 Hz) occurring near the binding site.
- Scalar coupling perturbations were also detected at sites distant from the direct ligand binding site, indicating allosteric effects.
- These coupling constant perturbations correlated with substantial structural rearrangements, particularly in backbone hydrogen bonding patterns.
Conclusions:
- Amide scalar coupling perturbation mapping serves as a valuable adjunct to chemical shift perturbation mapping in biomolecular NMR.
- This technique provides additional insights into both local and long-range, allosteric structural dynamics.
- It enhances the understanding of biomolecular interactions and conformational changes.
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