Site Directed Spin Labelling

Currently one of the most popular applications of pulse EPR are DEER/PELDOR measurements in conjunction with  site directed spin labelling. This technique involves attaching spin labels (usually radicals) to large molecules such as proteins and DNA. This can yield information about the immediate surroundings of the label position  and the interaction between two or more labels can give an indication of the structure of the molecule.

High-field EPR is particularly good for this application as it has sufficient resolution to resolve the spin label spectra, making it possible to make distance measurements from 2 nm to beyond 12 nm in deuterated protein systems.

PELDOR measurements are one of the key applications for our new W-band high power pulse spectrometer HiPER.  This instrument can provide extremely high sensitivity in combination with exquisite orientational sensitivity (in orientated systems).