Band-selective editing of exchange-relay in protein-water NOE experiments.

A pulse sequence is proposed which uses a train of band-selective pulses for the editing of slow chemical exchange-relay effects in experiments designed to study water-macromolecule interactions. Compared to previous methods, this experiment does not require knowledge of the exact chemical shift of the relaying labile protons and needs only the recording of a single experiment to edit the relay through different exchanging groups resonating at different frequencies. The pulse sequence has been implemented using Gaussian cascades and was applied to the study of the hydration of HEW lysozyme.