Transverse Relaxation During the Magnetization Transfer Steps

Let us consider a Hn- l 5N spin pair - the transverse relaxation T2 for the 15N spin (and HN as well) is mainly dictated by the dipole-dipole (DD) interaction between the spin pair, and the chemical shift anisotropy (CSA) of 

Exploitation of the TROSY effect is rather straightforward. In contrast to 15N-HSQC (Heteronuclear Single Quantum Coherence) or standard triple-resonance experiments based on 15N-HSQC, no radio frequency pulses or composite pulse decoupling should be applied on amide protons when HN spin is not in the transverse plane. Likewise the 15N decoupling should be 

At this point, before going into the details of triple-resonance experiments, we shift the focus to the polarization transfer step. Throughout this 

The last 90° pulse on 13C acts as a purge pulse for the undesired dispersive magnetization.47,48 The function of the pulse is to convert any magnetization remaining antiphase with respect to the 13C spin into unobservable multiple-quantum coherence. This will provide cross peaks with pure lineshapes and with higher resolution, and consequently establishes reliable determination of coupling constants.47,48 

Beside intra- and interresidue 13C nuclei, the magnetization can be transferred from the 15N spin directly to the 13C nuclei of the preceding 

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Transverse Relaxation During the Magnetization Transfer Steps 249... 

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