This work demonstrates the feasibility of using Gd(III) tags for long-range Double Electron Electron Resonance (DEER) distance measurements in biomacromolecules. Double-stranded 14- base pair Gd(III)-DNA conjugates were synthesized and investigated at Ka band. For the longest Gd(III) tag the average distance and average deviation between Gd(III) ions determined from the DEER time domains was about 59 ± 12 . This result demonstrates that DEER measurements with Gd(III) tags can be routinely carried out for distances of at least 60 , and analysis indicates that distance measurements up to 100 are possible. Compared with commonly used nitroxide labels, Gd(III)-based labels will be most beneficial for the detection of distance variations in large biomacromolecules, with an emphasis on large scale changes in shape or distance. Tracking the folding/unfolding and domain interactions of proteins and the conformational changes in DNA are examples of such applications.
- Distance measurements
- Gd(III) tags
- Pulse Dipolar Spectroscopy (PDS)
ASJC Scopus subject areas
- Nuclear and High Energy Physics
- Condensed Matter Physics