DEPT spectral editing in HCCONH-type experiments. Application to fast protein backbone and side chain assignment

Area of Science:

• Structural Biology
• Biophysical Chemistry
• Nuclear Magnetic Resonance Spectroscopy

Background:

• Protein resonance assignment is crucial for understanding protein structure and function.
• Traditional methods for protein resonance assignment can be time-consuming and complex.
• Aliphatic side chains present unique challenges in NMR spectral assignment.

Purpose of the Study:

• To introduce novel 2D Nuclear Magnetic Resonance (NMR) experiments for rapid aliphatic protein side chain resonance assignment.
• To demonstrate the utility of these experiments in assigning protein spectra.
• To complement existing NMR techniques for protein structure determination.

Main Methods:

• Development and application of 2D DEPT-H(alpha,beta)C(alpha,beta)(CO)NH and 2D CT-DEPT-HC(CO)NH-TOCSY experiments.
• Utilizing reduced-dimensionality NMR with frequency labeling of multiple nuclei.
• Employing DEPT spectral editing for peak reduction and amino acid type determination.

Main Results:

• Successful fast resonance assignment of aliphatic protein side chains was achieved.
• The experiments were validated on both small (68-residue) and highly deuterated (167-residue) proteins.
• DEPT spectral editing effectively reduced spectral complexity and aided assignment.

Conclusions:

• The presented 2D NMR experiments offer an efficient approach for aliphatic side chain assignment.
• These methods enhance the speed and accuracy of protein resonance assignment.
• The new experiments provide valuable additions to the toolkit for protein structural studies.