Related Experiment Video
Updated: Jul 1, 2025
11:19
Site Directed Spin Labeling and EPR Spectroscopic Studies of Pentameric Ligand-Gated Ion Channels
Published on: July 4, 2016
10.6K
Conformational Heterogeneity of β-Barrel Membrane Proteins Observed In Situ Using Orthogonal Spin Labels and Pulsed
Sophie Ketter1, Aathira Gopinath1,2, Benesh Joseph3
1Institute of Biophysics, Department of Physics, Goethe University Frankfurt, Frankfurt/Main, Germany.
Methods in Molecular Biology (Clifton, N.J.)
|March 13, 2024
Summary
This study details a protocol for site-directed spin labeling of outer membrane proteins in bacteria. It enables direct observation of protein structure and dynamics in their native environments using electron spin resonance techniques.
Area of Science:
- Biochemistry
- Biophysics
- Microbiology
Background:
- Outer membrane proteins (OMPs) are crucial for Gram-negative bacterial cell function.
- OMPs reside in the asymmetric lipid bilayer of the bacterial outer membrane.
- Understanding OMP structure and dynamics is key to deciphering their roles.
Purpose of the Study:
- To provide a detailed protocol for site-directed spin labeling (SDSL) of bacterial outer membrane proteins.
- To enable direct observation of protein structure and dynamics within their native cellular environment.
- To facilitate the application of advanced electron spin resonance (ESR) techniques.
Main Methods:
- Site-directed spin labeling (SDSL) using nitroxide, trityl, and Gd3+-based spin tags.
- Application of labeling to isolated outer membranes and intact E. coli.
- Continuous wave (CW) and pulsed electron-electron double resonance (PELDOR) measurements at Q-band (34 GHz).
Main Results:
- Demonstration of a robust protocol for labeling bacterial OMPs.
- Successful application of SDSL in both isolated membranes and intact cells.
- Establishment of experimental and data analysis procedures for ESR measurements.
Conclusions:
- The presented protocol allows for direct structural and dynamic studies of OMPs in their native bacterial context.
- This method enhances the understanding of OMP function and interactions.
- The described ESR techniques provide valuable insights into membrane protein biophysics.
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