Targetable Tetrazine-Based Dynamic Nuclear Polarization Agents for Biological Systems.

Area of Science:

• Biochemistry
• Chemical Biology
• Spectroscopy

Background:

• Dynamic nuclear polarization (DNP) significantly enhances nuclear magnetic resonance (NMR) sensitivity for biomolecules.
• Current DNP methods lack specificity, making it challenging to isolate signals from target proteins within complex cellular environments.

Purpose of the Study:

• To develop a novel DNP agent for selective targeting of proteins within living cells.
• To enable site-specific DNP-enhanced NMR spectroscopy in biological systems.

Main Methods:

• Introduction of an unnatural amino acid (UAA), norbornene-lysine, into proteins via genetic methods.
• Design and synthesis of a tetrazine-based DNP agent for bio-orthogonal conjugation to the UAA.
• Application of the targeted DNP agent in bacterial and mammalian cells.
• Investigation of DNP polarization-transfer mechanisms.

Main Results:

• Demonstrated selective DNP agent targeting to proteins bearing norbornene-lysine.
• Successfully enhanced NMR signals of targeted proteins in cellular settings.
• Elucidated complex polarization-transfer pathways in targeted DNP.

Conclusions:

• The developed tetrazine-based DNP agent provides a bio-orthogonal and adaptable method for selective protein labeling.
• This approach facilitates site-specific DNP-enhanced NMR spectroscopy in complex biological samples.
• The findings pave the way for advanced cellular NMR studies with improved sensitivity and specificity.