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Solution structure of omega-conotoxin MVIIA using 2D NMR spectroscopy
V J Basus1, L Nadasdi, J Ramachandran
1Department of Pharmaceutical Chemistry, University of California, San Francisco 94143, USA.
FEBS Letters
|August 21, 1995
Summary
The solution structure of omega-conotoxin MVIIA (SNX-111), a potent N-type calcium channel blocker, was elucidated using NMR. This peptide toxin exhibits structural similarity to conotoxin GVIA despite low sequence homology.
Area of Science:
- Biochemistry
- Structural Biology
- Neuroscience
Background:
- Omega-conotoxin MVIIA (SNX-111) is a peptide toxin from Conus magus.
- It functions as a high-affinity blocker of N-type calcium channels.
- Understanding its structure is crucial for neuropharmacology.
Purpose of the Study:
- To determine the solution structure of omega-conotoxin MVIIA (SNX-111).
- To provide insights into its mechanism of action as a calcium channel blocker.
Main Methods:
- Two-dimensional Nuclear Magnetic Resonance (2D NMR) spectroscopy was employed.
- Analysis of 44 structural models yielded an average pairwise RMSD of 0.59 angstroms.
Main Results:
- The determined structure reveals a short triple-stranded beta-sheet involving specific residues (6-8, 20-21, 24-25).
- The overall structure closely resembles that of omega-conotoxin GVIA.
- Despite only 40% sequence homology, structural similarity correlates with comparable calcium channel binding affinity and selectivity.
Conclusions:
- The determined solution structure of omega-conotoxin MVIIA provides a 3D molecular model.
- Structural similarity to conotoxin GVIA explains shared functional properties despite sequence divergence.
- This research aids in understanding peptide-toxin interactions with ion channels.