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Updated: May 25, 2026
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Atomic Scale Structural Studies of Macromolecular Assemblies by Solid-state Nuclear Magnetic Resonance Spectroscopy
Published on: September 17, 2017
Computed and experimental chemical shift parameters for rigid and flexible YAF peptides in the solid state
Tomasz Pawlak1, Katarzyna Trzeciak-Karlikowska, Jiri Czernek
1Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, PL-90-363 Lodz, Poland.
The Journal of Physical Chemistry. B
|January 14, 2012
Summary
This study used density functional theory (DFT) to analyze peptide crystal structures. Comparing computed and experimental data revealed that (13)C chemical shift tensor correlations offer insights into molecular motion dynamics.
Area of Science:
- Solid-state Nuclear Magnetic Resonance (NMR) Spectroscopy
- Computational Chemistry
- Crystallography
- Peptide Science
Background:
- Understanding molecular motion in peptide crystals is crucial for structure-property relationships.
- Different stereoisomers of Tyr-Ala-Phe (YAF) peptides exhibit distinct crystal packing and dynamics.
- Nuclear Magnetic Resonance (NMR) spectroscopy is a powerful tool for probing molecular dynamics in solids.
Purpose of the Study:
- To compute (13)C Nuclear Magnetic Resonance (NMR) chemical shift tensor (CST) parameters for YAF peptide crystals with varying alanine stereochemistry.
- To correlate theoretical CST calculations with experimental NMR data to understand molecular motion.
- To investigate the utility of (13)C CST correlations for analyzing local molecular dynamics in crystalline peptides.
Main Methods:
- Density Functional Theory (DFT) calculations were employed to determine (13)C CST parameters.
- Solid-state NMR techniques, including PISEMA MAS and (2)H QUADECHO experiments, were used to analyze molecular motion.
- Experimental (13)C CST parameters were measured using a 2D PASS NMR sequence.
Main Results:
- Distinct molecular motions were observed for the tyrosine and phenylalanine rings in different YAF peptide crystal forms.
- Sample 1 (Tyr-D-Ala-Phe) showed rigid tyrosine and phenylalanine rings undergoing π-jumps.
- Sample 2a (Tyr-L-Ala-Phe in P2(1)2(1)2) exhibited static rings, while Sample 2b (Tyr-L-Ala-Phe in P6(5)) displayed fast exchange dynamics.
- Good correlation between computed and experimental (13)C CST parameters was found for sample 2a, with significant scatter for samples 1 and 2b.
- The quality of (13)C CST correlations provides valuable information on local molecular motions.
Conclusions:
- The study demonstrates the sensitivity of (13)C CST parameters to local molecular motions in peptide crystals.
- Proper interpretation of (13)C CST correlations can elucidate the dynamics of specific molecular segments.
- DFT calculations, when validated against experimental NMR data, serve as a reliable method for studying peptide dynamics.
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