1H-detected magic-angle spinning NMR experiments facilitate structural biology of solid proteins, which requires using deuterated proteins. However, often amide protons cannot be back-exchanged sufficiently, because of a possible lack of solvent exposure. For such systems, using 2H excitation instead of 1H excitation can be beneficial because of the larger abundance and shorter longitudinal relaxation time, T1, of deuterium. A new structure determination approach, "quadruple-resonance NMR spectroscopy", is presented which relies on an efficient 2H-excitation and 2H-13C cross-polarization (CP) step, combined with 1H detection. We show that by using 2H-excited experiments better sensitivity is possible on an SH3 sample recrystallized from 30 % H2O. For a membrane protein, the ABC transporter ArtMP in native lipid bilayers, different sets of signals can be observed from different initial polarization pathways, which can be evaluated further to extract structural properties. Proton-detected magic-angle spinning solid-state NMR spectroscopy using deuterated proteins facilitates structural biology. Solid deuterated proteins that cannot be unfolded/refolded to exchange the deuterons back with protons and proteins that can only be studied in their native environments show a low intrinsic sensitivity in NMR experiments. For such systems, initial excitation of the deuterons can be very useful.
All Science Journal Classification (ASJC) codes
- high sensitivity
- quadruple-resonance MAS NMR spectroscopy
- structure elucidation