A heteronuclear correlation experiment for simultaneous determination of 15N longitudinal decay and chemical exchange rates of systems in slow equilibrium.

A heteronuclear correlation experiment is described which permits simultaneous characterization of both 15N longitudinal decay rates and slow conformational exchange rates. Data pertaining to the exchange between folded and unfolded forms of an SH3 domain is used to illustrate the technique. Because the unfolded form of the molecule, on average, shows significantly higher NH exchange rates than the folded form, an approach which minimizes the degree of water saturation is employed, enabling the extraction of accurate rate constants.