The Nuclear Overhauser Effect

Abstract

The nuclear Overhauser effect (NOE) is observed as a change in intensity of one resonance when the intensity of a neighboring resonance is perturbed. The effect depends strongly on the internuclear distance r, in that the rate of transmission of the NOE is proportional to r -6. However, various factors conspire to reduce this dependence, making reliable quantitation of distances difficult. Nevertheless, the technique is widely used, particularly in the structure determination of biomolecules and as a routine method for conformational analysis in chemistry. The introduction of new methodology has greatly extended its use for conformational analysis, measurement of intermolecular interactions, and analysis of ligand binding. Thus, although our understanding of the theory of the NOE has not changed much in recent years, the areas of application continue to increase.