Selective Protein Hyperpolarization in Cell Lysates Using Targeted Dynamic Nuclear Polarization.

Area of Science:

• Biochemistry
• Biophysics
• Structural Biology

Background:

• Nuclear magnetic resonance (NMR) spectroscopy is powerful for studying proteins in native environments.
• Traditional NMR requires high protein purity and concentration, which are often unnatural.
• Achieving sufficient signal-to-noise ratio in complex biological samples remains a challenge.

Purpose of the Study:

• To develop an efficient and specific method for hyperpolarizing low amounts of target proteins within complex biological mixtures.
• To enable the study of proteins at near-native concentrations and in more native environments using NMR.
• To overcome the limitations of traditional NMR requiring highly purified protein samples.

Main Methods:

• Combining dynamic nuclear polarization (DNP) with the selectivity of protein-protein or protein-ligand interactions.
• Utilizing a biradical-labeled ligand to direct hyperpolarization specifically to the target protein.
• Applying the technique to filter and enhance signals from target proteins in crude cell lysates.

Main Results:

• Achieved significant signal enhancement in target proteins using approximately 400-fold fewer radicals compared to conventional DNP methods.
• Successfully isolated and hyperpolarized target proteins directly from crude cell lysate derived from small volumes (8 mL) of isotope-enriched cell culture.
• Demonstrated the ability to study proteins at near-native concentrations, improving signal detection.

Conclusions:

• The developed method efficiently hyperpolarizes target proteins in complex biological backgrounds.
• This technique significantly reduces the need for high protein purity and concentration in NMR studies.
• The approach facilitates the atomic-resolution investigation of proteins in increasingly native cellular environments.