Solid-State NMR/Dynamic Nuclear Polarization of Polypeptides in Planar Supported Lipid Bilayers

Area of Science:

• Solid-state Nuclear Magnetic Resonance (NMR) Spectroscopy
• Dynamic Nuclear Polarization (DNP)
• Biophysical Chemistry

Background:

• Low signal intensity is a major limitation in NMR spectroscopy, especially for solid-state samples.
• Dynamic Nuclear Polarization (DNP) is a technique used to enhance NMR signal intensity.
• Solid-state NMR often requires specialized probes for low gamma nuclei and broadened signals.

Purpose of the Study:

• To develop a novel triple-resonance flat-coil solid-state NMR probe with microwave irradiation capabilities.
• To enable the investigation of static samples, including supported lipid bilayers, at low temperatures (100 K).
• To improve signal-to-noise ratios and spectral resolution in solid-state NMR experiments.

Main Methods:

• Development of a triple-resonance flat-coil probe with integrated microwave irradiation.
• Implementation of high-power Lee-Goldberg decoupling and cross-polarization with gyrotron microwave irradiation.
• Optimization of sample preparation, including membrane-anchored biradicals and supported membrane geometry for heat and microwave dissipation.

Main Results:

• Achieved signal enhancement factors of up to 17-fold.
• Obtained a 2D PISEMA spectrum of a transmembrane helical peptide in under 2 hours.
• Demonstrated the probe's capability for high-quality 2D separated local field experiments.

Conclusions:

• The developed solid-state NMR probe significantly overcomes signal intensity limitations using DNP.
• The probe facilitates detailed structural and dynamic studies of challenging biological systems like lipid bilayers.
• This advancement extends the applicability of solid-state NMR for static samples and low gamma nuclei.