A Benchmark Study of Protein-Fragment Complex Structure Calculations with NMR²

Area of Science:

• Structural biology
• Medicinal chemistry
• Biophysics

Background:

• Protein-ligand complex structures are crucial for rational drug design.
• X-ray crystallography is common but has a high failure rate.
• Nuclear Magnetic Resonance (NMR) is an alternative but hindered by time-consuming protein signal assignment.

Purpose of the Study:

• To evaluate the performance of NMR Molecular Replacement (NMR2) for protein-fragment complex structure determination.
• To identify challenges in calculating protein-fragment complex structures using NMR.
• To propose strategies for improving the success rate of NMR2 in this application.

Main Methods:

• Benchmarking the NMR2 method with the SERAPhic fragment library.
• Applying NMR2 to elucidate protein-fragment complex structures.
• Analyzing technical challenges in NMR structure calculation for small fragments.

Main Results:

• NMR2 demonstrates expected performance in determining protein-fragment complex structures.
• The study identified specific technical challenges associated with small fragment sizes (<300 Da).
• A straightforward strategy was proposed to enhance the success rate of NMR2.

Conclusions:

• NMR2 is a versatile and rapid method for protein-fragment complex structure elucidation.
• NMR2 presents a viable alternative to X-ray crystallography for these challenging structures.
• The proposed strategy can further improve the applicability of NMR2 in fragment-based drug discovery.