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Updated: Jul 19, 2026
11:19
Site Directed Spin Labeling and EPR Spectroscopic Studies of Pentameric Ligand-Gated Ion Channels
Published on: July 4, 2016
Distance determination in human ubiquitin by pulsed double electron-electron resonance and double quantum coherence
1ESR Division, Bruker Biospin K.K., Ibaraki 305-0051, Japan. Hideyuki.hara@bruker-biospin.jp
Journal of Magnetic Resonance (San Diego, Calif. : 1997)
|October 19, 2006
Summary
We compared two electron spin resonance methods, pulsed DEER and DQC-ESR, for measuring distances in proteins. Both techniques successfully determined distances in human ubiquitin, offering valuable insights into protein structure.
Area of Science:
- Biophysics
- Structural Biology
- Spectroscopy
Background:
- Pulsed electron spin resonance (ESR) techniques like pulsed DEER and DQC are used for distance measurements in proteins via site-directed spin labeling (SDSL).
- These methods can probe long-range dipole interactions, typically between 15-80 Angstroms.
Purpose of the Study:
- To apply and compare pulsed DEER and DQC-ESR methods for distance measurements in human ubiquitin.
- To estimate the distance between specific cysteine residues (20th and 35th) in doubly spin-labeled human ubiquitin.
Main Methods:
- Utilized pulsed DEER (double electron-electron resonance) and DQC-ESR (double quantum coherence ESR) on a commercial pulsed ESR spectrometer.
- Applied site-directed spin labeling (SDSL) to human ubiquitin.
Main Results:
- Successfully applied both pulsed DEER and DQC-ESR to human ubiquitin.
- Estimated the distance between the 20th and 35th cysteine residues in doubly spin-labeled human ubiquitin.
- Highlighted the operational differences: pulsed DEER typically doesn't require phase cycling, while DQC-ESR at X-band can yield large signals but may face electron spin echo envelope modulation (ESEEM) issues.
Conclusions:
- Both pulsed DEER and DQC-ESR are viable methods for long-range distance measurements in proteins using SDSL.
- The study provides a comparative analysis of these techniques in the context of human ubiquitin structure determination.
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