Optimal control pulses for the 1.2 GHz (28.2 T) NMR spectrometers

The ability to measure NMR spectra with a large sample volume is crucial for concentration limited biological samples in order to attain adequate signal-to-noise (S/N) ratio. The possibility to measure with a 5 mm cryoprobe is currently absent at the 1.2 GHz NMR instruments due to the exceedingly high radio frequency power demands, which is four times compared to a 600 MHz instruments. Here, we overcome the high power demands by designing optimal control (OC) pulses with up to 20 times lower power requirements than currently necessary at a 1.2 GHz spectrometer. We show that multidimensional biomolecular NMR experiments constructed using these OC pulses can bestow improvement in the S/N ratio of up to 26%. With the expected power limitations of a 5 mm cryoprobe, we observe an enhancement in the S/N ratio of more than 240% using our OC sequences. This motivates the development of a cryoprobe with a larger volume than the current 3 mm cryoprobes. , , , All the reported OC pulses, pulse sequence codes and the necessary parameter files to reproduce the results on a Bruker Avance Neo 1200 MHz using Topspin software is provided here.

All the pulse shapes are in the Bruker file format (see the Topspin documentation for shape pulses more information on the file structure).

Data S1. Optimal control pulse shapes reported in this work. The data file oc_waves contains the following optimal control pulse shapes. In the folder UR_shapes are the UR shapes,

The universal rotation (UR) pulse name has the following naming scheme
UR_(nuclei)*(nuation angle)*(pulse duration)*(bandwidth)*(RF amplitude)_(B1 miscalibration)

1. UR_1H_180deg_700us_BW_15kHz_RFA_8kHzB1inho20per.dajo
2. UR_15N_180deg_700us_BW_6kHz_RFA_5kHzB1inho20per.dajo
3. UR_1H_180deg_540us_BW_12_6kHz_RFA_7_5kHz_B1d_15per.dajo
4. UR_15N_180deg_540us_BW_4_8kHz_RFA_5kHz_B1d_15per.dajo
5. UR_1H_90deg_650us_BW_15kHz_RFA_8kHzB1d20per.dajo
6. UR_15N_90deg_650us_BW_6kHz_RFA_5kHzB1inho20per.daj...