For large ²H-labeled proteins in high magnetic fields, it can be better to use NMR pulse sequences that afford improved sensitivity and resolution by means of the TROSY effect and better ¹³C relaxation properties. This experiment is a modified version of the 3D HNCO experiment with the following differences:

The last PEP building block has been substituted by a TROSY block

Deuterium decoupling is applied during the ¹³C-evolution t₁ period when the magnetization is on the alpha carbons.

¹H-decoupling is removed during the ¹⁵N evolution t₂ constant-time periods and ¹⁵N-decoupling is removed during acquisition

Experimental:

Create a new dataset (new) and read the standard BRUKER parameter set (rpar) to record a 3D HNCO experiment using TROSY by typing rpar TRHNCOGP2H3D all. The pulse program trhncogp2h3d can be visualized in the PulsProg section or with the edcpul command).

Update the corresponding pulses and power levels in the acquisition parameters according to the selected solvent/probehead parameters by executing the getprosol command (pulses and power levels must be correctly set by the edprosol command). The major modifications, with respect to the original experiment, are the following:

• The nucleus on f4 channel is defined as NUC4=2H
• o4p=3.0ppm, centered to the ²H aliphatic region.
• Deuteron decoupling is achieved by applying cpdgrp4=waltz16, at power level pl17, using a decoupling pulse length about pcpd4=300us.
• Accurate calibration of the duration of the selective 90 water pulse (p11) and its power level (sp1) can be achieved by minimizing the first serial data.

See Related HNCO Experiments