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Atomic Scale Structural Studies of Macromolecular Assemblies by Solid-state Nuclear Magnetic Resonance Spectroscopy
Published on: September 17, 2017
13C and 15N spectral editing inside histidine imidazole ring through solid-state NMR spectroscopy
Shenhui Li1, Lei Zhou, Yongchao Su
1State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, The Chinese Academy of Sciences, Wuhan 430071, China. lishenhui@wipm.ac.cn
Solid State Nuclear Magnetic Resonance
|June 5, 2013
Summary
Solid-state NMR methods distinguish histidine forms by analyzing imidazole ring chemical shifts. These shifts correlate with atomic charge, providing insights into proton transfer in biological systems.
Area of Science:
- Biochemistry
- Chemical Physics
- Molecular Biology
Background:
- Histidine exists in multiple protonation and tautomerization states at physiological pH.
- These states influence biological processes and can be characterized by imidazole ring chemical shifts.
Purpose of the Study:
- To develop solid-state Nuclear Magnetic Resonance (NMR) techniques for spectral editing of histidine's imidazole ring.
- To establish a benchmark for distinguishing different histidine forms.
- To investigate the relationship between chemical shifts and atomic charge.
Main Methods:
- Solid-state NMR spectroscopy.
- Spectral editing techniques targeting specific (13)C and (15)N sites.
- One-bond homo- and hetero-nuclear dipole interactions for site selection.
- Theoretical calculations of atomic charges and chemical shifts.
Main Results:
- Successful spectral editing of (13)Cγ, (13)Cδ2, (15)Nδ1, and (15)Nε2 sites in the histidine imidazole ring.
- Demonstrated a roughly linear correlation between (1)H, (13)C, and (15)N chemical shifts and atomic charge.
- Attributed chemical shift variations to atomic charge changes during proton transfer.
Conclusions:
- Developed a reliable NMR-based method to differentiate histidine's various forms.
- Established a link between histidine's chemical shifts, atomic charge, and proton transfer dynamics.
- Provided a valuable tool for studying histidine's role in biological systems.
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