Proton assisted recoupling at high spinning frequencies

Area of Science:

• Solid-state Nuclear Magnetic Resonance (NMR) Spectroscopy
• Biophysical Chemistry
• Structural Biology

Background:

• High-resolution structural studies of proteins are essential for understanding their function.
• Magic Angle Spinning (MAS) NMR is a powerful technique for protein structure determination.
• Achieving optimal resolution and preserving protein integrity under MAS conditions remains a challenge.

Purpose of the Study:

• To demonstrate the successful application of (13)C-(13)C proton assisted recoupling (PAR) for structural analysis of proteins.
• To achieve high-resolution 2D spectra with long-range (13)C-(13)C contacts at high MAS frequencies.
• To enable distance measurements for protein structural studies under specific experimental conditions.

Main Methods:

• Application of (13)C-(13)C proton assisted recoupling (PAR) on uniformly labeled [U-(13)C,(15)N] N-f-MLF-OH and protein GB1.
• Utilizing high magic angle spinning (MAS) frequencies (ω(r)/2π = 65 kHz).
• Combining PAR mixing with low power heteronuclear decoupling (ω(1H)/2π ≈ 16 kHz).

Main Results:

• Successful acquisition of high-resolution 2D spectra.
• Observation of long-range (13)C-(13)C contacts.
• Extraction of distance estimates from the obtained spectra.

Conclusions:

• Proton assisted recoupling (PAR) is successfully applied to protein samples at high MAS frequencies.
• This technique allows for high-resolution structural studies, including distance measurements.
• The experimental regime of high spinning frequency and low power (1)H decoupling optimizes protein NMR resolution and sample integrity.