New pulsed field gradient NMR experiments for the detection of bound water in proteins

Abstract

New H(2)O-selective homonuclear and heteronuclear 2D NMR experiments have been designed for the observation of protein hydration (PHOGSY, Protein Hydration Observed by Gradient Spectroscop Y). These experiments utilize selective excitation of the H(2)O resonance and pulsed field gradients for coherence selection and efficient H(2)O suppression. The method allows for a rapid and sensitive detection of H(2)O molecules in labelled and unlabelled proteins. In addition it opens a way to measure the residence time of water bound to proteins. Its application to uniformly (15)N-labelled FKBP-12 (FK-506 binding protein) is demonstrated.