Accelerating proton spin diffusion in perdeuterated proteins at 100 kHz MAS.
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.
Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, 8093, Zurich, Switzerland.
Johannes J
JJ
Wittmann
Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, 8093, Zurich, Switzerland.|TIFR Center for Interdisciplinary Science, 21 Brundavan Colony, Narsingi, Hyderabad, 500075, India.
Vipin
V
Agarwal
Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, 8093, Zurich, Switzerland.
Johannes
J
Hellwagner
Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, 8093, Zurich, Switzerland.
Alons
A
Lends
Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, 8093, Zurich, Switzerland.
Riccardo
R
Cadalbert
Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, 8093, Zurich, Switzerland. beme@ethz.ch.
Beat H
BH
Meier
Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, 8093, Zurich, Switzerland. maer@ethz.ch.
Matthias
0000-0002-9538-6086
M
Ernst
D000465:Algorithms; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008962:Models, Theoretical; D011506:Proteins / Q000737:chemistry*; D011522:Protons; D025801:Ubiquitin / Q000737:chemistry
D011506:Proteins; D011522:Protons; D025801:Ubiquitin
Fast MAS; Protein structure determination; Spin diffusion