3D MAS NMR Experiment Utilizing Through-Space ¹⁵N-¹⁵N Correlations

Area of Science:

• Biophysics
• Structural Biology
• Nuclear Magnetic Resonance (NMR) Spectroscopy

Background:

• Solid-state NMR is crucial for determining protein structures.
• Current methods for obtaining protein structural information using NMR have limitations in resolution and sensitivity.

Purpose of the Study:

• To introduce a novel 3D NNC magic angle spinning NMR experiment.
• To improve the resolution and signal-to-noise ratio in solid-state NMR studies of proteins.
• To provide a complementary strategy for backbone chemical shift assignments and distance constraints.

Main Methods:

• Development of a 3D NNC magic angle spinning NMR experiment.
• Utilized an optimized 15N-15N proton-assisted recoupling (PAR) mixing period.
• Incorporated a 13C dimension for enhanced spectral resolution.

Main Results:

• Successfully generated 15N-15N internuclear contacts in protein systems.
• Acquired high signal-to-noise 3D NMR data.
• Demonstrated the experiment's utility on an M0Aβ1-42 fibril sample, yielding high-quality, interpretable data.
• Enabled backbone chemical shift assignments and provided distance constraints.

Conclusions:

• The 3D NNC NMR experiment is a powerful new tool for solid-state protein studies.
• The optimized PAR conditions enhance data quality for structural analysis.
• This method is broadly applicable to diverse protein systems and experimental conditions.