Nanosecond Time Scale Motions in Proteins Revealed by High-Resolution NMR Relaxometry

Abstract

Understanding the molecular determinants underlying protein function requires the characterization of both structure and dynamics at atomic resolution. Nuclear relaxation rates allow a precise characterization of protein dynamics at the Larmor frequencies of spins. This usually limits the sampling of motions to a narrow range of frequencies corresponding to high magnetic fields. At lower fields one cannot achieve sufficient sensitivity and resolution in NMR. Here, we use a fast shuttle device where the polarization builds up and the signals are detected at high field, while longitudinal relaxation takes place at low fields 0.5 < B0 < 14.1 T. The sample is propelled over a distance up to 50 cm by a blowgun-like system in about 50 ms. The analysis of nitrogen-15 relaxation in the protein ubiquitin over such a wide range of magnetic fields offers unprecedented insights into molecular dynamics. Some key regions of the protein feature structural fluctuations on nanosecond time scales, which have so far been overlooked in high-field relaxation studies. Nanosecond motions in proteins may have been underestimated by traditional high-field approaches, and slower supra-τc motions that have no effect on relaxation may have been overestimated. High-resolution relaxometry thus opens the way to a quantitative characterization of nanosecond motions in proteins.

Adaptive resolution simulation of a biomolecule and its hydration shell: Structural and dynamical properties

“…64 Meanwhile, NMR order parameters show a strong field dependence. 65 Our aim here is to show that our AdResS methodology reproduces physical reality as correctly as possible using existing force fields and to the limit at which physical reality can be known using current experimental techniques.…”

“…(b) NMR order parameter S 2 of the protein backbone amide NH bonds. Comparison between AdResS system and experimental results: (c) X-ray crystallographic B-factors47,64,109 and (d) experimentally determined S 2 order parameters 65,110. …”

A fast field-cycling device for high-resolution NMR: Design and application to spin relaxation and hyperpolarization experiments

“…Moreover, such studies are often technically easier because of the longer ܶ ଵ -relaxation times of 13 C, 15 N and 31 P and, in principle, they enable [8,35,50,53] studies of intramolecular mobility of biomolecules. Also, polarization transfer experiments can be straightforwardly extended to heteronuclei.…”

“…There are only a few examples [27,35,[50][51][52][53] of site-specific relaxation studies, in which Nuclear Magnetic Relaxation Dispersion (NMRD) was measured for individual atoms. Such experiments give a way to obtain information about mobility with atomic resolution.…”

Structural Dynamic Study of Roof Waterproofing Materials

“…It should be noted that the study of NMR spectra is based on the resonating nuclei systems that are extremely sensitive to the magnetic environment where the local magnetic fields near the resonating nuclei are dependent on the intra-and intermolecular effects. This determines the value of NMR spectroscopy to investigate the structure and behavior of many-electron (molecular) systems in different fields of science (Washburn and Birdwell, 2013;Nascimento, et al, 2004;Bayer, et al, 2010;Berman, et al, 2013;Charlier, et al, 2013;Kemalov, et al, 2012;Kruk et al, 2012, Twieg, 2013, Frantsuzov, 2010.…”