Monitoring Conformational Changes in an Enzyme Conversion Inhibitor Using Pure Shift Exchange NMR Spectroscopy

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Organic Chemistry

Background:

• Nuclear Magnetic Resonance (NMR) spectroscopy is vital for characterizing molecular dynamics.
• Exchange Spectroscopy (EXSY) is used to study chemical exchange processes.
• Standard 2D NMR EXSY can be limited by spectral resolution, especially for slow exchange processes.

Purpose of the Study:

• To develop and evaluate an ultrahigh-resolution 2D NMR EXSY technique.
• To improve the analysis of slow conformational exchange in pharmaceutical compounds.
• To demonstrate the robustness of the homonuclear decoupling method.

Main Methods:

• Implementation of interferogram-based PSYCHE (Pure Shift PSYCHE) homonuclear decoupling.
• Acquisition of pure shift 2D NMR EXSY spectra.
• Comparison of pure shift EXSY with standard EXSY experiments.

Main Results:

• Ultrahigh resolution achieved in 2D NMR EXSY spectra.
• Pure shift spectra allow for extraction of exchange rates coherent with standard methods.
• The method demonstrates robustness over a range of temperatures.
• Simplified proton line shapes enable probing of more proton sites.

Conclusions:

• Pure shift 2D NMR EXSY offers enhanced resolution for studying slow conformational exchange.
• This technique provides a more thorough and accurate analysis of chemical exchange processes.
• The method facilitates multi-site analysis, overcoming limitations of standard approaches.