sofast-HMQC and ultra-sofast-HMQC

Pulse sequence to record H-X SOFAST-hmqc

(where X=C or N) (Schanda et al.,2005,JBiomolNMR)

Bruker pulse sequence to record 2D SOFAST-hmqc experiments

Fig3. NMR generator run 2D H-N SOFAST-hmqc using below sample.#

#Sample: 0.02mM, 15N, 13C-labeled Ubiquitin in 20mM HEPES at pH 6.8 with 10% D2O

PULSE SEQUENCE DESCRIPTION (BRIEF)

Paul Schanda introduced SOFAST-hmqc experiments for proteins (varied size) measured at different magnetic fields. 2D heteronuclear NMR experiments (H-N or H-C) could be recorded in seconds (fast acquisition with shoter interscan delays) with significant gain in intensity than the conventional HSQC. It took the advantage of lesser number of rf pulses, Ernst angle excitation and optimized longitudinal relaxation. 2D SOFAST-hmqc when shooted with a biomolecule sample features H-X HMQC transfer with lesser number of rf pulses which limits signal loss and the band-selective 1H excitation reduce the effective T1 of observed protons in the sample. (more details in the paper Schanda et al.,2005,JBiomolNMR)

REFERENCES

1. Schanda et al.,2005, JBiomolNMR, SOFAST_HMQC experiments for recording two dimensional heteronuclear correlation spectra of proteins within a few seconds, 33:199-211

2. Fast-HMQC using Ernst angle pulses: An efficient tool for screening of ligand binding to target proteins.

3. An improved ultrafast 2D NMR experiment: Towards atom-resolved real-time studies of protein kinetics at multi-Hz rates

4. Longitudinal 1H Relaxation Optimization in TROSY NMR Spectroscopy

Ultra SOFAST HMQC

STS-ultraSOFAST-HMQC pulse sequence for performing fast 2D ¹H–¹⁵N correlation experiments of proteins. STS pulse sequence is enclosed by dotted grey box [adapted from Gal, M. et al, 2009].

Reference:

1. Gal M. et al. 2009, JBiomolNMR, "An improved ultrafst 2D NMR experiment: Towards atom-resolved real-time studies of protein kinetics at multi-Hz rates".

SOFAST NMR has also been used to study protein kinetics by modifying UltraSOFAST-HMQC pulse sequence to involve a single-transition-state (STS) pulse sequence element [Fig. 4]. This experiment (STS)-ultraSOFAST-HMQC has been demonstrated to measure H/D exchange in real-time ¹H-¹⁵N spectra at a rate of approximately 3 Hz