Structural NMR of protein oligomers using hybrid methods

Area of Science:

• Structural Biology
• Biophysics
• Computational Biology

Background:

• Traditional high-resolution Nuclear Magnetic Resonance (NMR) methods face challenges in solving the structures of native oligomeric protein complexes.
• Advancements in computational platforms and integration of diverse biophysical data offer new avenues for NMR-based structural determination.

Purpose of the Study:

• To review techniques providing complementary structural information for oligomeric protein complexes.
• To demonstrate a non-traditional approach for determining the structure of protein complexes, particularly weak homo-dimers.
• To illustrate the practical application of this approach using a chemokine tetramer structure.

Main Methods:

• Utilizing orientational constraints from residual dipolar couplings and residual chemical shift anisotropy offsets.
• Integrating orientational data with interaction site information from chemical shift perturbation, paramagnetic surface perturbation, cross-saturation, and mass spectrometry.
• Employing computational platforms for integrating multi-source data in structural modeling.
• Incorporating non-NMR techniques like Electron Paramagnetic Resonance (EPR) and small-angle X-ray scattering (SAXS).

Main Results:

• The combined approach simplifies the construction of models for oligomeric complexes, including weak homo-dimers.
• High-resolution models of protein complexes can be constructed with relative ease.
• Non-NMR techniques provide alternative methods for probing the overall shape of complexes.
• A detailed example demonstrates the successful determination of a chemokine tetramer structure.

Conclusions:

• A non-traditional, integrated approach significantly enhances the ability to determine the structures of challenging oligomeric protein complexes.
• The synergy between NMR, other biophysical methods, and computational modeling expands the scope of NMR-applicable targets.
• This strategy facilitates the construction of high-resolution structural models for complex biological assemblies.