TROSY-selected ZZ-exchange experiment for characterizing slow chemical exchange in large proteins

A TROSY-selected ZZ-exchange experiment is described for measuring slow chemical exchange rates by monitoring the TROSY component of (15)N longitudinal magnetization. Application of the proposed pulse sequence to the cadherin 8 N-terminal extracelluar domain demonstrates that enhanced sensitivity is obtained, compared to a previously described TROSY-detected ZZ-exchange sequence (Sahu et al. J Am Chem Soc 129: 13232-13237, 2007), by preserving the TROSY effect during the mixing period as well as the frequency encoding periods.