WaterControl [1,2] is an efficient water suppression technique based on the PGSTE-WATERGATE pulse sequence [3]. Unlike other common solvent elimination methods to date, this technique utilises the discriminating nature of diffusion-filtering of PGSTE [4] and the selective-inversion augmented by the magnetic field gradients of WATERGATE [5] to effectively reduce the large water signal in solution while leaving significant solute signals near the water resonance. This results in much cleaner spectra with additional peaks around the water region.
One potentially useful application of WaterControl is in the suppression of water signals in protein NMR studies. It was found recently [2], that NOESY experiments with WaterControl yield spectra with numerous NOE resonances around the water region along w1 and also along w2 which would otherwise be obliterated by common solvent suppression methods including WATERGATE. In this study, we appended WaterControl to other 2D protein NMR experiments such as TOCSY, optimised its performance and verified its usefulness. The use of WaterControl in protein NMR studies could be helpful in studying water bound to biomolecules [6] and could decrease the number of experiments needed to observe protein resonances near the water signal.