Paramagnetic Probes in Metalloproteins. Turning Limitations into Advantages

At the beginning of the 1990s, when obtaining solution structures of biomolecules by nuclear magnetic resonance (NMR) was already a well-established technique, it was commonly believed that solution structures of macromolecules containing paramagnetic centers could not be solved. Indeed, the loss of information arising from the hyperfine interaction between nuclear spins and the unpaired electron spin was supposed to be (i) too severe and (ii) unavoidable.