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Atomic Scale Structural Studies of Macromolecular Assemblies by Solid-state Nuclear Magnetic Resonance Spectroscopy
Published on: September 17, 2017
Magic angle spinning and oriented sample solid-state NMR structural restraints combine for influenza a M2 protein
Thach V Can1, Mukesh Sharma, Ivan Hung
1Department of Physics, Florida State University, Tallahassee, 32306, United States.
Journal of the American Chemical Society
|May 24, 2012
Summary
This study reveals the M2 proton channel
Area of Science:
- Biophysics
- Structural Biology
- Membrane Protein Research
Background:
- The M2 proton channel is a tetrameric helical membrane protein whose structure is sensitive to its environment.
- Understanding its structure in a lipid bilayer is crucial for elucidating its conductance mechanism.
- Previous studies provided backbone structure but lacked detail on quaternary packing and side-chain conformations.
Purpose of the Study:
- To determine the quaternary structure and stability of the M2 proton channel within a lipid bilayer.
- To investigate the role of His37 in stabilizing the tetrameric structure.
- To showcase the power of combining solid-state NMR techniques for membrane protein structure determination.
Main Methods:
- Magic angle spinning (MAS) solid-state NMR on liposomal preparations.
- Analysis of isotropic chemical shift data.
- Identification of interhelical cross peaks.
Main Results:
- Strong support for a dimer-of-dimers quaternary structure of the transmembrane helical bundle.
- Explanation for enhanced tetrameric stability upon charge absorption by the His37 tetrad.
- Demonstration of the utility of combined solid-state NMR approaches.
Conclusions:
- The M2 proton channel adopts a dimer-of-dimers structure in lipid bilayers.
- Charge absorption by His37 is key to the channel's tetrameric stability and activation.
- Combined solid-state NMR techniques are powerful for characterizing helical membrane protein structures.
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