In vivo NMR field-cycling relaxation spectroscopy reveals14N1H relaxation sinks in the backbones of proteins

Reports on the first in vivo study using NMR field-cycling relaxation spectroscopy. The species investigated was Hirudo medicinalis (leech). Clear 14 N 1 H quadrupole dips have been observed. Thus the authors have proven that the amide 14 N 1 H groups of proteins can act as relaxation sinks in a frequency range relevant for NMR tomography. as the 14 N 1 H interaction is modulated by any motion of the protein backbones, it is the dynamics of proteins which, in addition to the water content, determines water proton relaxation in biological cells.