Disentangling the Complexity in Protein Complexes Using Complementary Isotope-Labeling and Multiple-Receiver NMR...

Area of Science:

• Biochemistry
• Structural Biology
• Molecular Biophysics

Background:

• Intrinsically disordered proteins (IDPs) are crucial in eukaryotic systems but challenging pharmacological targets.
• Nuclear Magnetic Resonance (NMR) spectroscopy offers atomistic insights into protein interactions but faces challenges like spectral overlap and sample limitations.
• Studying IDPs and their interactions is vital for understanding cellular processes and developing new therapeutics.

Purpose of the Study:

• To develop a novel NMR-based approach for simultaneously mapping protein-protein binding sites on interacting partners.
• To overcome limitations of traditional NMR methods in studying complex protein interactions, particularly for IDPs.
• To demonstrate the utility of the proposed method using a biologically significant protein complex.

Main Methods:

• Employing a complementary isotope-labeling strategy with differential labeling of interacting partners (e.g., 15N,2H and 13C,1H).
• Utilizing a multiple receiver NMR detection scheme for enhanced signal clarity and reduced spectral overlap.
• Applying proton and carbon detection to obtain clean and interpretable data for binding site identification.

Main Results:

• Successfully mapped protein-protein binding sites on two interacting partners simultaneously.
• Obtained clean and easily readable NMR data, overcoming spectral complexity issues.
• Demonstrated the method's effectiveness on a 50 kDa ternary complex involving Myc/MAX and BRCA1.

Conclusions:

• The proposed NMR approach enables efficient and simultaneous mapping of protein-protein binding sites.
• This method significantly improves the study of intrinsically disordered proteins and their interactions.
• The technique provides a valuable tool for drug discovery targeting protein-protein interactions.