CPMG R2 Relaxation Rate Dispersion

Accurate R2 value, without any contribution from such exchange, is determined by applying a series of k pulses (Tcp-TT—r p) whose repetition rate (1 /Tcp) is higher than the exchange rate by using Carr-Purcell-Meiboom-GiU 

Distinguishing fast from slow exchange may be feasible by CPMG measurements at two values of the external field oc Am in fast exchange, 

The use of constant-time (CT) CPMG periods that effectively remove complications owing to scalar coupling and cross-correlated relaxation allows measurement of a complete dispersion curve in a short time [83]. The values of i -2,e F for this experiment were calculated for each i cpmg value using the relationship  

Studies on dynamic processes by CPMG, based on transverse relaxation rates, are limited to relatively small ( 20 kDa) proteins. TROSY [85] (transverse relaxation optimized spectroscopy) CPMG, however, extends the size limitation (up to a 54 kDa) imposed on relaxation measurements due to the fast decay of transverse magnetization in larger macromole-cules [86]. Further, CT TROSY-based CPMG pulse sequences were utilized for measuring double (DQ), zero (ZQ), and single 

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