Microsecond motions probed by near-rotary-resonance R1ρ15N MAS NMR experiments: the model case of protein overall-rocking in crystals.
Abstract
Solid-state near-rotary-resonance measurements of the spin-lattice relaxation rate in the rotating frame (R1ρ) is a powerful NMR technique for studying molecular dynamics in the microsecond time scale. The small difference between the spin-lock (SL) and magic-angle-spinning (MAS) frequencies allows sampling very slow motions, at the same time it brings up some methodological challenges. In this work, several issues affecting correct measurements and analysis of 15N R1ρ data are considered in detail. Among them are signal amplitude as a function of the difference between SL and MAS frequencies, "dead time" in the initial part of the relaxation decay caused by transient spin-dynamic oscillations, measurements under HORROR condition and proper treatment of the multi-exponential relaxation decays. The multiple 15N R1ρ measurements at different SL fields and temperatures have been conducted in 1D mode (i.e. without site-specific resolution) for a set of four different microcrystalline protein samples (GB1, SH3, MPD-ubiquitin and cubic-PEG-ubiquitin) to study the overall protein rocking in a crystal. While the amplitude of this motion varies very significantly, its correlation time for all four sample is practically the same, 30-50 μ...Continue Reading
References
Citations
Effect of Post-Translational Modifications and Mutations on Amyloid-β Fibrils Dynamics at N Terminus
Deuteron Chemical Exchange Saturation Transfer for the Detection of Slow Motions in Rotating Solids.
Methods Mentioned
Related Concepts
Related Feeds
Brucellosis
Brucellosis is a bacterial infection caused by members of the genus brucella and remains one of the world's major zoonotic diseases. Discover the latest research on Brucellosis here.
Brucellosis (ASM)
Brucellosis is a bacterial infection caused by members of the genus brucella and remains one of the world's major zoonotic diseases. Discover the latest research on Brucellosis here.