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Updated: Dec 30, 2025
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Atomic Scale Structural Studies of Macromolecular Assemblies by Solid-state Nuclear Magnetic Resonance Spectroscopy
Published on: September 17, 2017
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Magnetic Alignment of Polymer Nanodiscs Probed by Solid-State NMR Spectroscopy
Thirupathi Ravula1, JaeWoong Kim2, Dong-Kuk Lee2
1Biophysics Program and Department of Chemistry, Macromolecular Science and Engineering, Biomedical Engineering , University of Michigan , Ann Arbor , Michigan 48109-1055 , United States.
Langmuir : the ACS Journal of Surfaces and Colloids
|January 22, 2020
Summary
Styrene maleimide quaternary ammonium (SMA-QA) polymer nanodiscs spontaneously align in magnetic fields, enabling solid-state NMR studies of membrane proteins. Adding lanthanide salts allows control over nanodisc orientation for advanced structural analysis.
Area of Science:
- Biophysics
- Materials Science
- Structural Biology
Background:
- Amphipathic polymers enable lipid nanodisc formation for membrane protein studies.
- Polymer nanodiscs offer magnetic alignment, unlike detergent micelles.
- Magnetic alignment is crucial for solid-state NMR and residual dipolar coupling measurements.
Purpose of the Study:
- To investigate the magnetic alignment properties of styrene maleimide quaternary ammonium (SMA-QA) polymer nanodiscs.
- To assess the utility of SMA-QA nanodiscs for solid-state NMR applications.
- To explore methods for controlling nanodisc orientation using external stimuli.
Main Methods:
- Utilized 31P and 14N solid-state NMR spectroscopy.
- Performed experiments under static magnetic field conditions.
- Investigated the effect of paramagnetic lanthanide salts on nanodisc alignment.
Main Results:
- Demonstrated spontaneous magnetic alignment of SMA-QA nanodiscs (≥20 nm diameter).
- Observed nanodisc alignment with the lipid bilayer normal perpendicular to the magnetic field.
- Showed that lanthanide salts can flip the nanodisc alignment axis parallel to the magnetic field.
Conclusions:
- SMA-QA polymer nanodiscs exhibit controllable magnetic alignment properties.
- These nanodiscs are suitable for solid-state NMR applications, including membrane protein structural studies.
- The ability to manipulate nanodisc orientation enhances their utility in biophysical investigations.
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