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Published on: December 27, 2016
51V solid-state magic angle spinning NMR spectroscopy of vanadium chloroperoxidase
Neela Pooransingh-Margolis1, Rokus Renirie, Zulfiqar Hasan
1Brown Laboratories, Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA.
Journal of the American Chemical Society
|April 13, 2006
Summary
We used 51V solid-state NMR to study vanadium chloroperoxidase. This technique successfully probed the vanadium center, revealing its coordination environment and electronic structure.
Area of Science:
- Biophysical Chemistry
- Structural Biology
- Nuclear Magnetic Resonance Spectroscopy
Background:
- Vanadium chloroperoxidase is a metalloprotein containing a single vanadium atom per molecule.
- Understanding the coordination environment of vanadium is crucial for elucidating enzyme function.
- Previous methods have limitations in providing detailed structural information about the vanadium center.
Purpose of the Study:
- To apply 51V solid-state NMR spectroscopy to directly probe the vanadium center in vanadium chloroperoxidase.
- To determine the quadrupolar and chemical shift anisotropy tensors of the vanadium site.
- To elucidate the geometric and electronic structure of the vanadium cofactor.
Main Methods:
- High-field (14.1 T) 51V solid-state NMR spectroscopy.
- Numerical simulations of spinning sideband envelopes and line shapes.
- Density functional theory (DFT) calculations of active site models.
Main Results:
- The spinning sideband manifold of the central and satellite transitions was readily detectable despite low vanadium concentration.
- The quadrupolar coupling constant (C(Q)) was determined to be 10.5 ± 1.5 MHz.
- The chemical shift anisotropy (Δσ) was determined to be -520 ± 13 ppm.
- DFT calculations suggest an anionic vanadate cofactor with specific hydroxo and oxo ligands.
Conclusions:
- 51V solid-state NMR is a powerful technique for directly investigating the vanadium center in metalloproteins.
- The determined spectroscopic parameters provide sensitive insights into the vanadium coordination environment.
- This approach is expected to be broadly applicable to other diamagnetic vanadium-containing proteins.
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