LowCOST-HSQC Variants for Fast-Pulsing High ω₁-Resolved 2D Experiments

Area of Science:

• Nuclear Magnetic Resonance Spectroscopy
• Biophysical Chemistry

Background:

• Sensitivity enhancement is crucial for analyzing low-abundance nuclei (e.g., Carbon-13, Nitrogen-15) in biomolecules.
• Standard HSQC experiments can be time-consuming due to limited sensitivity.

Purpose of the Study:

• To introduce and compare INEPT-type transfer elements for the Low-field Optimized Constant-time Sensitivity Transfer-Heteronuclear Single Quantum Coherence (LowCOST-HSQC) experiment.
• To evaluate different variants of the LowCOST-HSQC pulse sequence.

Main Methods:

• Detailed theoretical description of three INEPT-type transfer elements: original LowCOST, ZIP, and TIG-BIRD.
• Evaluation of various LowCOST-HSQC pulse sequence configurations.
• Utilizing fast polarization distribution via isotropic mixing for rapid 2D experiment acquisition.

Main Results:

• Demonstrated that LowCOST-HSQC retains unused proton polarization for improved sensitivity.
• Showcased the capability for fast-pulsing 2D experiments.
• Provided a comparative analysis of different INEPT-type transfer elements within the LowCOST framework.

Conclusions:

• LowCOST-HSQC is an effective sensitivity-enhanced technique for correlating with low natural abundance nuclei.
• The choice of INEPT-type transfer element impacts the performance of LowCOST-HSQC experiments.
• This method facilitates faster acquisition of 2D NMR data, particularly for challenging samples.