Wang Songlin, Ravula Thirupathi, Stringer John A, Gor'kov Peter L, Warmuth Owen A, Williams Christopher G, Thome Alex F, Mueller Leonard J, Rienstra Chad M
bioRxiv. 2025 May 6:2025.05.05.652283. doi: 10.1101/2025.05.05.652283.
NMR spectroscopy is a powerful technique with broad impact across the physical and life sciences, and ultra-high field, GHz-class NMR spectrometers offer exceptional overall performance including superior resolution and sensitivity. While the resolution is fundamentally limited by molecular tumbling for solution NMR, solid-state NMR (SSNMR) is constrained only by instrumentation, making it well-suited for studying large and complex systems. To fully leverage UHF magnets for magic-angle-spinning SSNMR, it is essential to eliminate linebroadening arising from magnetic field drift and couplings among the nuclear spins. We address these challenges using an external H lock to compensate the field drift and Long-Observation-Window Band-Selective Homonuclear Decoupling (LOW-BASHD) to suppress C homonuclear couplings. We thereby achieve better than 0.2 ppm resolution in proteins up to 144 kDa, enabling unique site resolution for over 500 amide backbone pairs in 2D experiments. This exceeds the resolution available from solution NMR for large biological molecules, greatly expanding the potential of GHz-class NMR for research in life sciences.
Ultra-high field NMR enables scientists to observe the finest details of large biomolecules, and this study overcomes key challenges to achieve a new benchmark for resolution in solid-state NMR of high molecular weight proteins.
核磁共振光谱是一项强大的技术，对物理和生命科学有着广泛影响，超高频、千兆赫兹级别的核磁共振光谱仪具有卓越的整体性能，包括超高分辨率和灵敏度。虽然对于溶液核磁共振，分辨率从根本上受分子翻滚限制，但固态核磁共振（SSNMR）仅受仪器限制，这使其非常适合研究大型复杂系统。为了充分利用超高频磁体进行魔角旋转固态核磁共振，消除由磁场漂移和核自旋间耦合引起的线宽展宽至关重要。我们通过使用外部氢锁来补偿场漂移，并采用长观测窗口带选择同核去耦（LOW - BASHD）来抑制碳同核耦合，从而应对这些挑战。由此，我们在高达144 kDa的蛋白质中实现了优于0.2 ppm的分辨率，在二维实验中为超过500个酰胺主链对实现了独特的位点分辨率。这超过了大型生物分子溶液核磁共振所能达到的分辨率，极大地扩展了千兆赫兹级核磁共振在生命科学研究中的潜力。
超高场核磁共振使科学家能够观察大型生物分子的最细微细节，这项研究克服了关键挑战，为高分子量蛋白质固态核磁共振的分辨率树立了新的标杆。
