Nanomole-scale protein solid-state NMR by breaking intrinsic 1H T1 boundaries

Solid-state NMR spectroscopy is used to elucidate structural details about proteins that cannot be easily studied by X-ray crystallography, but because the technique is not very sensitive, large sample amounts are required, limiting its biological application. A combination of optimizations now increases the sensitivity of solid-state NMR spectroscopy by up to 5-fold. We present an approach that accelerates protein solid-state NMR 5–20-fold using paramagnetic doping to condense data-collection time (to ∼0.2 s per scan), overcoming a long-standing limitation on slow recycling owing to intrinsic 1 H T 1 longitudinal spin relaxation. Using low-power schemes under magic-angle spinning at 40 kHz, we obtained two-dimensional 13 C- 13 C and 13 C- 15 N solid-state NMR spectra for several to tens of nanomoles of β-amyloid fibrils and ubiquitin in 1–2 d.