Time-sharing evolution and sensitivity enhancements in 2D HSQC-TOCSY and HSQMBC experiments

Area of Science:

• Biophysical Chemistry
• Structural Biology
• Nuclear Magnetic Resonance Spectroscopy

Background:

• Time-shared (TS) HSQC-like experiments are established NMR techniques.
• Extracting diverse information often requires separate, sequential NMR experiments.

Purpose of the Study:

• To propose modifications of TS HSQC-like experiments for simultaneous data acquisition.
• To demonstrate enhanced sensitivity and expanded information content from a single NMR pulse scheme.

Main Methods:

• Modification of existing time-shared HSQC-like NMR pulse sequences.
• Simultaneous acquisition of 1H,13C HSQC-TOCSY and 1H,15N HSQMBC experiments.
• Incorporation of independent editing elements for spectral assignment and coupling measurements.

Main Results:

• Achieved experimental sensitivity enhancements of 20-40% compared to separate acquisitions.
• Enabled unambiguous assignment of 1H, 13C, and 15N chemical shifts.
• Facilitated simultaneous measurement of long-range proton-carbon and proton-nitrogen coupling constants.

Conclusions:

• The proposed NMR methodologies offer increased efficiency and comprehensive data acquisition.
• These methods are applicable to various nitrogen-containing compounds, as demonstrated with cyclosporine.
• Simultaneous acquisition strategies significantly improve NMR data utility and experimental throughput.