A STUDY OF PROTEIN-WATER EXCHANGE THROUGH THE OFF-RESONANCE ROESY EXPERIMENT - APPLICATION TO THE DNA-BINDING DOMAIN OF ALCR

In this communication a new NMR experiment for the safe observation an d quantification of water-protein exchange phenomena is presented. It combines a water-selective pulse, offering chemical shift-based separa tion, and the off-resonance ROESY dynamic filter, which permits the el imination of the unwanted intramolecular dipolar cross relaxation of p rotein protons. Moreover, pulsed field gradients are used for the supp ression of radiation damping and the solvent signal. The straightforwa rd incorporation of this sequence in heteronuclear experiments is demo nstrated for the case of the DNA-binding domain of the alcohol regulat or protein.