Pulsed field gradient NMR and nuclear magnetic relaxation studies of water mobility in hydrated collagen II.

Transverse nuclear magnetic relaxation and self-diffusion of water were measured in hydrated collagen II. Self-diffusion measurements were conducted by pulsed field gradient NMR (PFG NMR) and weighting of the different species in the signal by variable T2 relaxation in the experiment. Two fractions of water protons were detected, one with a short T2 value but high diffusivity and one with a long T2 value and low, completely restricted diffusion. The distance of the diffusion barriers was determined to be 2.3 microns. Possible reasons for the restriction in the movement of the water molecules in comparison with structural models of collagen II are discussed.