Accelerating proton spin diffusion in perdeuterated proteins at 100 kHz MAS
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Fast magic-angle spinning (>60 kHz) has many advantages but makes spin-diffusion-type proton–proton long-range polarization transfer inefficient and highly dependent on chemical-shift offset. Using 100%-HN-[2H,13C,15N]-ubiquitin as a model substance, we quantify the influence of the chemical-shift difference on the spin diffusion between proton spins and compare two experiments which lead to an improved chemical-shift compensation of the transfer: rotating-frame spin diffusion and a new experiment, reverse amplitude-modulated MIRROR. Both approaches enable broadband spin diffusion, but the application of the first variant is limited due to fast spin relaxation in the rotating frame. The reverse MIRROR experiment, in contrast, is a promising candidate for the determination of structurally relevant distance restraints. The applied tailored rf-irradiation schemes allow full control over the range of recoupled chemical shifts and efficiently drive spin diffusion. Here, the relevant relaxation time is the larger longitudinal relaxation time, which leads to a higher signal-to-noise ratio in the spectra.
KeywordsFast MAS Protein structure determination Spin diffusion
- Demers J-P, Chevelkov V, Lange A (2011) Progress in correlation spectroscopy at ultra-fast magic-angle spinning: basic building blocks and complex experiments for the study of protein structure and dynamics. Solid State Nucl Magn Reson 40:101–113. doi:10.1016/j.ssnmr.2011.07.002 CrossRefGoogle Scholar
- Ishii Y (2001) [sup 13]C–[sup 13]C dipolar recoupling under very fast magic angle spinning in solid-state nuclear magnetic resonance: applications to distance measurements, spectral assignments, and high-throughput secondary-structure determination. J Chem Phys 114:8473. doi:10.1063/1.1359445 ADSCrossRefGoogle Scholar
- Meier BH (1994) Polarization transfer and spin diffusion in solid-state NMR. Adv Magn Opt Reson 18:1Google Scholar