Solution NMR of polypeptides hyperpolarized by dynamic nuclear polarization

Area of Science:

• Nuclear Magnetic Resonance (NMR) Spectroscopy
• Biophysics
• Chemical Physics

Background:

• Dynamic Nuclear Polarization (DNP) enhances NMR signal-to-noise ratios, enabling study of dynamic processes.
• Solid-to-liquid state DNP has primarily been applied to small molecules.

Purpose of the Study:

• To demonstrate the feasibility of solid-to-liquid state DNP for larger biomolecules, specifically a peptide (bacitracin A) and a full-length protein (L23).
• To explore the potential of hyperpolarized NMR for studying protein dynamics and interactions.

Main Methods:

• Hyperpolarization of nuclear spins in solid-state peptides and proteins using DNP at low temperatures.
• Dissolution of hyperpolarized samples into liquid mixtures (organic solvent/water) for NMR signal acquisition.
• Analysis of hyperpolarized 13C and 1H NMR spectra, including spectral simulation and relaxation parameter measurements.

Main Results:

• Achieved signal enhancements of 300-2000 for 13C and 30-180 for 1H in partially deuterated polypeptides.
• Successfully demonstrated solid-to-liquid state DNP for a full-length protein (L23), expanding its application beyond small molecules.
• Correlated observed signal enhancements with measured relaxation parameters in hyperpolarized protein samples.

Conclusions:

• Solid-to-liquid state DNP is a feasible technique for hyperpolarizing larger proteins.
• This method holds significant potential for advancing the study of protein folding and macromolecular interactions using NMR spectroscopy.