PHRONESIS: A One-Shot Approach for Sequential Assignment of Protein Resonances by Ultrafast MAS Solid-State NMR Spectroscopy

Solid-state NMR (ssNMR) spectroscopy has emerged as the method of choice to analyze the structural dynamics of fibrillar, membrane-bound, and crystalline proteins that are recalcitrant to other structural techniques. Recently, H-1 detection under fast magic angle spinning and multiple acquisition ssNMR techniques have propelled the structural analysis of complex biomacromolecules. However, data acquisition and resonance-specific assignments remain a bottleneck for this technique. Here, we present a comprehensive multi-acquisition experiment (PHRONESIS) that simultaneously generates up to ten 3D H-1-detected ssNMR spectra. PHRONESIS utilizes broadband transfer and selective pulses to drive multiple independent polarization pathways. High selectivity excitation and de-excitation of specific resonances were achieved by high-fidelity selective pulses that were designed using a combination of an evolutionary algorithm and artificial intelligence. We demonstrated the power of this approach with microcrystalline U-C-13,N-15 GB1 protein, reaching 100 % of the resonance assignments using one data set of ten 3D experiments. The strategy outlined in this work opens up new avenues for implementing novel H-1-detected multi-acquisition ssNMR experiments to speed up and expand the application to larger biomolecular systems.

Automated summary

Solid-state NMR spectroscopy is a preferred method for analyzing the structural dynamics of challenging proteins. Researchers have developed a new approach (PHRONESIS) that allows for the simultaneous generation of multiple 3D H-1-detected ssNMR spectra, leading to significant advancements in structural analysis.