Enhanced solid-state NMR sensitivity of α-synuclein fibrils using a MAS cryoprobe

Solid-state NMR spectroscopy is increasingly used to investigate the structure and dynamics of a wide range of chemical, material, and biological systems. Although limited sensitivity has long posed a major challenge, the recently developed MAS cryoprobe substantially alleviates this limitation. By enhancing the signal-to-noise (S/N) ratio without requiring sample freezing, the MAS cryoprobe is particularly well suited for studies of non-isotropic systems, including rigid solids (e.g., amyloid fibrils), semi-solids (e.g., membrane mimetics), and soft materials (e.g., nanodiscs and hydrogels). In this study, we demonstrate the enhanced sensitivity of solid-state NMR experiments on α-synuclein fibrils using a MAS cryoprobe. Compared with a conventional MAS probe, substantial improvements in S/N were observed in CPMAS, refocused INEPT, and 2D 13 C 13 C chemical-shift correlation spectra. The increased sensitivity enables the detection of slowly decaying signals in the indirect dimension, thereby accelerating the acquisition of high-resolution multidimensional solid-state NMR data. These results highlight the potential of MAS cryoprobes for structural studies of samples that are scarce, unstable, or transient, such as amyloid intermediaries.