title: Slow motions in microcrystalline proteins as observed by MAS-dependent 15N rotating-frame NMR relaxation.
abstract: (15)N NMR relaxation rate R1ρ measurements reveal that a substantial fraction of residues in the microcrystalline chicken alpha-spectrin SH3 domain protein undergoes dynamics in the μs-ms timescale range. On the basis of a comparison of 2D site-resolved with 1D integrated (15)N spectral intensities, we demonstrate that the significant fraction of broad signals in the 2D spectrum exhibits the most pronounced slow mobility. We show that (15)N R1ρ's in proton-diluted protein samples are practically free from the coherent spin-spin contribution even at low MAS rates, and thus can be analysed quantitatively. Moderate MAS rates (10-30 kHz) can be more advantageous in comparison with the rates >50-60 kHz when slow dynamics are to be identified and quantified by means of R1ρ experiments.
authors.affiliation: Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, Betty-Heimann-Str.7, D-06120 Halle, Germany. Electronic address: krushelnitsky@physik.uni-halle.de.
authors.forename: Alexey
authors.initials: A
authors.lastname: Krushelnitsky
authors.affiliation: Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, Betty-Heimann-Str.7, D-06120 Halle, Germany.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Zinkevich
authors.affiliation: Department Chemie, Technische Universität München (TUM), Lichtenbergstr. 4, D-85747 Garching, Germany.
authors.forename: Bernd
authors.initials: B
authors.lastname: Reif
authors.affiliation: Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, Betty-Heimann-Str.7, D-06120 Halle, Germany.
authors.forename: Kay
authors.initials: K
authors.lastname: Saalwächter
mesh_terms: D000465:Algorithms; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D009038:Motion; D009587:Nitrogen Isotopes / Q000032:analysis / Q000737:chemistry; D011487:Protein Conformation; D012815:Signal Processing, Computer-Assisted; D013049:Spectrin / Q000737:chemistry* / Q000648:ultrastructure*; D018909:src Homology Domains
chemical_list: D009587:Nitrogen Isotopes; D013049:Spectrin
keywords: Dynamics; Magic angle spinning; Relaxation; SH3 domain; Solid-state