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Updated: May 6, 2026

15N CPMG Relaxation Dispersion for the Investigation of Protein Conformational Dynamics on the µs-ms Timescale
Published on: April 19, 2021
Visualizing side chains of invisible protein conformers by solution NMR
Guillaume Bouvignies1, Pramodh Vallurupalli1, Lewis E Kay2
1Department of Molecular Genetics, The University of Toronto, Toronto, Ontario M5S 1A8, Canada; Department of Biochemistry, The University of Toronto, Toronto, Ontario M5S 1A8, Canada; Department of Chemistry, The University of Toronto, Toronto, Ontario M5S 1A8, Canada.
This study introduces a new NMR method to analyze rare protein structures using side-chain (13)C chemical shifts. This technique provides atomic-level insights into protein folding and dynamics, crucial for understanding biochemical processes.
Area of Science:
- Biochemistry
- Structural Biology
- Nuclear Magnetic Resonance (NMR) Spectroscopy
Background:
- Sparsely populated protein conformers are crucial for biochemical processes but difficult to study.
- Standard biophysical techniques often fail to capture these transient states.
- Previous NMR methods focused on backbone nuclei, limiting side-chain analysis.
Purpose of the Study:
- To develop an NMR method for analyzing side-chain dynamics in rare protein conformers.
- To assign side-chain aliphatic (13)C chemical shifts in uniformly (13)C labeled proteins.
- To gain atomic-resolution insights into protein folding intermediates and dynamics.
Main Methods:
- Development of a (13)C-based chemical exchange saturation transfer (CEST) experiment.
- Application to uniformly (13)C labeled proteins, specifically Fyn SH3 and FF domains.
- Assignment of side-chain aliphatic (13)C chemical shifts for excited states.
Main Results:
- Successfully obtained over 96% of side-chain (13)C chemical shifts for the unfolded Fyn SH3 domain.
- Achieved 89% assignment for the FF domain folding intermediate.
- Provided detailed insight into side-chain packing and dynamics in transient protein states.
Conclusions:
- The developed (13)C-CEST NMR method effectively characterizes rare protein conformers.
- This technique enhances understanding of protein structure-function relationships by detailing side-chain behavior.
- The findings offer new avenues for studying protein folding and dynamics at atomic resolution.
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