TY - JOUR
T1 - Sensitivity enhancement using paramagnetic relaxation in MAS solid-state NMR of perdeuterated proteins
AU - Linser, Rasmus
AU - Chevelkov, Veniamin
AU - Diehl, Anne
AU - Reif, Bernd
N1 - Funding Information:
We thank Kristina Rehbein for providing the triply labeled protein. The authors are grateful to Prof. Hartmut Oschkinat for continuous support of this project. We thank Tomas Jacso, Katja Faelber, Mangesh Joshi, Vipin Agarval, Muralidhar Dasari, and Uwe Fink for a lot of help and stimulating discussion. R.L. is a Kekulé scholar and acknowledges support from the Verband der Chemischen Industrie. This research was supported by the DFG Grant Re1435.
PY - 2007/12
Y1 - 2007/12
N2 - Previously, Ishii et al., could show that chelated paramagnetic ions can be employed to significantly decrease the recycle delay of a MAS solid-state NMR experiment [N.P. Wickramasinghe, M. Kotecha, A. Samoson, J. Past, Y. Ishii, Sensitivity enhancement in C-13 solid-state NMR of protein microcrystals by use of paramagnetic metal ions for optimizing H-1 T-1 relaxation, J. Magn. Reson. 184 (2007) 350-356]. Application of the method is limited to very robust samples, for which sample stability is not compromised by RF induced heating. In addition, probe integrity might be perturbed in standard MAS PRE experiments due to the use of very short duty cycles. We show that these deleterious effects can be avoided if perdeuterated proteins are employed that have been re-crystallized from D2O:H2O = 9:1 containing buffer solutions. The experiments are demonstrated using the SH3 domain of chicken α-spectrin as a model system. The labeling scheme allows to record proton detected 1H, 15N correlation spectra with very high resolution in the absence of heteronuclear dipolar decoupling. Cu-edta as a doping reagent yields a reduction of the recycle delay by up to a factor of 15. In particular, we find that the 1H T1 for the bulk HN magnetization is reduced from 4.4 s to 0.3 s if the Cu-edta concentration is increased from 0 mM to 250 mM. Possible perturbations like chemical shift changes or line broadening due to the paramagnetic chelate complex are minimal. No degradation of our samples was observed in the course of the experiments.
AB - Previously, Ishii et al., could show that chelated paramagnetic ions can be employed to significantly decrease the recycle delay of a MAS solid-state NMR experiment [N.P. Wickramasinghe, M. Kotecha, A. Samoson, J. Past, Y. Ishii, Sensitivity enhancement in C-13 solid-state NMR of protein microcrystals by use of paramagnetic metal ions for optimizing H-1 T-1 relaxation, J. Magn. Reson. 184 (2007) 350-356]. Application of the method is limited to very robust samples, for which sample stability is not compromised by RF induced heating. In addition, probe integrity might be perturbed in standard MAS PRE experiments due to the use of very short duty cycles. We show that these deleterious effects can be avoided if perdeuterated proteins are employed that have been re-crystallized from D2O:H2O = 9:1 containing buffer solutions. The experiments are demonstrated using the SH3 domain of chicken α-spectrin as a model system. The labeling scheme allows to record proton detected 1H, 15N correlation spectra with very high resolution in the absence of heteronuclear dipolar decoupling. Cu-edta as a doping reagent yields a reduction of the recycle delay by up to a factor of 15. In particular, we find that the 1H T1 for the bulk HN magnetization is reduced from 4.4 s to 0.3 s if the Cu-edta concentration is increased from 0 mM to 250 mM. Possible perturbations like chemical shift changes or line broadening due to the paramagnetic chelate complex are minimal. No degradation of our samples was observed in the course of the experiments.
KW - Deuteration
KW - MAS solid-state NMR
KW - Magic angle spinning
KW - Micro-crystals
KW - Paramagnetic relaxation enhancement
UR - http://www.scopus.com/inward/record.url?scp=35748978521&partnerID=8YFLogxK
U2 - 10.1016/j.jmr.2007.09.007
DO - 10.1016/j.jmr.2007.09.007
M3 - Article
C2 - 17923428
AN - SCOPUS:35748978521
SN - 1090-7807
VL - 189
SP - 209
EP - 216
JO - Journal of Magnetic Resonance
JF - Journal of Magnetic Resonance
IS - 2
ER -