TROSY principle

For a N-labeled protein of 150 kDa at 750 MHz and 20°C, one predicts residual linewidths of 10 Hz for and 45 Hz for H, and for the corresponding uniformly N, H-labeled protein the residual linewidths are predicted to be smaller than 5 and 15 Hz, respectively. The TROSY principle should benefit a variety of multidimensional solution NMR experiments, especially with future use of yet somewhat higher polarizing magnetic fields than are presently available, and thus largely eliminate one of the key factors that limit work with larger molecules (Pervushin et al. 1997). 

In principle, TROSY is not limited to interference between dipole-dipole coupling and CSA. Pervushin [50] proposed the use of the differential conformational exchange-in-... 

The relaxation theory used in the Appendix to describe the principle of TROSY clearly tells us what to expect, but it is always a little more satisfying if one can obtain a simple physical picture of what is happening. We consider a system of two isolated scalar coupled spins of magnitude %, 1H (I) and 15N (S), with a scalar coupling constant JHN. Transverse relaxation of this spin system is dominated by the DD coupling between spins XH and 15N and by the CSA of each individual spin. The relaxation rates of the individual multiplet components of spin 15N are now discussed assuming an axially symmetric 15N CSA tensor with the axial principal component parallel to the 15N-XH vector as shown in Fig. 10.2. 

Double-resonance Experiments. - TROSY-type experiments have been traditionally based on the cross-correlation between dipolar and chemical shift anisotropy relaxation mechanisms. Tugarinov et al. extended the application of the relaxation compensation principles to cancellation of the intra-methyl H- H and dipole-dipole interactions. The analysis of the relaxation of the... 

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