A Spectral Window in Protein NMR Revealing Cross-Relaxation between Amide Protons

摘要

The principle of quenching undesirable indirect external trouble in nuclear Overhauser effect spectroscopy (QUIET-NOESY) relies on a doubly selective inversion of the longitudinal magnetization components of a source spin A and a target spin X to measure the cross-relaxation rate (Overhauser effect) between A and X without significant perturbation by spin diffusion. In ~(15)N-enriched proteins, this can be achieved by using a bilinear rotation decoupling (BIRD) sequence for the selective inversion of amide protons that have a scalar coupling to nitrogen-15. The procedure can be improved by using editing techniques to simplify the resulting NOESY spectra.