Long range information from electron paramagnetic resonance

Electron paramagnetic resonance (EPR) spectroscopy offers unique possibilities to measure very long range distances between two paramagnetic centres in biomolecules in the range of 1.5- 8 nm with high accuracy and sensitivity. Flexibility of paramagnetic tags, however, complicates the interpretation of the measured distances in respect to tagged proteins. By modelling the covalent attachment of lanthanide tags computationally we have shown that long range EPR distance measurements can be more accurately interpreted in terms of the actual protein structure.