Differential line broadening in MAS solid-state NMR due to dynamic interference.
Many MAS (magic angle spinning) solid-state NMR investigations of biologically relevant protein samples are hampered by poor resolution, particularly in the 15N chemical shift dimension. We show that dynamics in the nanosecond-microsecond time scale in solid-state samples can induce significant line broadening of 15N resonances in solid-state NMR experiments. Averaging of 15NH(alpha/beta) multiplet components due to 1H decoupling induces effective relaxation of the 15N coherence in case the N-H spin pair undergoes significant motion. High resolution solid-state NMR spectra can then only be recorded by application of TROSY (Transverse Relaxation Optimized Spectroscopy) type techniques which select the narrow component of the multiplet pattern. We speculate that this effect has been the major obstacle to the NMR spectroscopic characterization of many membrane proteins and fibrillar aggregates so far. Only in very favorable cases, where dynamics are either absent or very fast (picosecond), high-resolution spectra were obtained. We expect that this approach which requires intense deuteration will have a significant impact on the quality and the rate at which solid-state NMR spectroscopic investigations will emerge in the future.
Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Str. 10, D-13125 Berlin, Germany, and Charité Universitätsmedizin, D-10115 Berlin, Germany.
Veniamin
V
Chevelkov
Katja
K
Faelber
Anna
A
Schrey
Kristina
K
Rehbein
Anne
A
Diehl
Bernd
B
Reif
D000818:Animals; D002645:Chickens; D018360:Crystallography, X-Ray; D003903:Deuterium; D008958:Models, Molecular; D009587:Nitrogen Isotopes; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D011506:Proteins / Q000737:chemistry*; D013049:Spectrin / Q000737:chemistry; D018909:src Homology Domains
D009587:Nitrogen Isotopes; D011506:Proteins; D013049:Spectrin; D003903:Deuterium