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Slow Internal Protein Dynamics from Water 1H Magnetic Relaxation Dispersion

Persson Sunde, Erik LU and Halle, Bertil LU (2009) In Journal of the American Chemical Society 131(51). p.18214-18214
Abstract
To probe internal motions in proteins on the 10−8−10−5 s time scale by NMR relaxation, it is necessary to eliminate protein tumbling. Here, we examine to what extent magnetic relaxation dispersion (MRD) experiments on the water 1H resonance report on protein motions in this time window. We also perform a critical test of two physically distinct mechanisms that have been proposed to explain and interpret 1H MRD profiles from immobilized proteins: the exchange-mediated orientational randomization (EMOR) mechanism and the two-phase spin-fracton (2PSF) mechanism. For these purposes, we report the 1H MRD profiles from protonated and partially deuterated ubiquitin, cross-linked by glutaraldehyde. The EMOR approach, with the crystal structure of... (More)
To probe internal motions in proteins on the 10−8−10−5 s time scale by NMR relaxation, it is necessary to eliminate protein tumbling. Here, we examine to what extent magnetic relaxation dispersion (MRD) experiments on the water 1H resonance report on protein motions in this time window. We also perform a critical test of two physically distinct mechanisms that have been proposed to explain and interpret 1H MRD profiles from immobilized proteins: the exchange-mediated orientational randomization (EMOR) mechanism and the two-phase spin-fracton (2PSF) mechanism. For these purposes, we report the 1H MRD profiles from protonated and partially deuterated ubiquitin, cross-linked by glutaraldehyde. The EMOR approach, with the crystal structure of ubiquitin as input, accounts quantitatively for the MRD data and shows that hydroxyl-bearing side chains undergo large-amplitude motions on the microsecond time scale. In contrast, the 2PSF model, which attributes 1H relaxation to small-amplitude backbone vibrations that propagate in a low-dimensional fractal space, fails qualitatively in describing the effect of H→D substitution. These findings appear to resolve the long-standing controversy over the molecular basis of water-1H relaxation in systems containing rotationally immobilized macromolecules, including biological tissue. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of the American Chemical Society
volume
131
issue
51
pages
18214 - 18214
publisher
The American Chemical Society
external identifiers
  • wos:000273615800012
  • scopus:73249145811
ISSN
1520-5126
DOI
10.1021/ja908144y
language
English
LU publication?
yes
id
8ff86e98-cdbb-4cda-a009-28708b5fa117 (old id 1520917)
date added to LUP
2010-01-05 11:57:31
date last changed
2017-09-24 04:10:22
@article{8ff86e98-cdbb-4cda-a009-28708b5fa117,
  abstract     = {To probe internal motions in proteins on the 10−8−10−5 s time scale by NMR relaxation, it is necessary to eliminate protein tumbling. Here, we examine to what extent magnetic relaxation dispersion (MRD) experiments on the water 1H resonance report on protein motions in this time window. We also perform a critical test of two physically distinct mechanisms that have been proposed to explain and interpret 1H MRD profiles from immobilized proteins: the exchange-mediated orientational randomization (EMOR) mechanism and the two-phase spin-fracton (2PSF) mechanism. For these purposes, we report the 1H MRD profiles from protonated and partially deuterated ubiquitin, cross-linked by glutaraldehyde. The EMOR approach, with the crystal structure of ubiquitin as input, accounts quantitatively for the MRD data and shows that hydroxyl-bearing side chains undergo large-amplitude motions on the microsecond time scale. In contrast, the 2PSF model, which attributes 1H relaxation to small-amplitude backbone vibrations that propagate in a low-dimensional fractal space, fails qualitatively in describing the effect of H→D substitution. These findings appear to resolve the long-standing controversy over the molecular basis of water-1H relaxation in systems containing rotationally immobilized macromolecules, including biological tissue.},
  author       = {Persson Sunde, Erik and Halle, Bertil},
  issn         = {1520-5126},
  language     = {eng},
  number       = {51},
  pages        = {18214--18214},
  publisher    = {The American Chemical Society},
  series       = {Journal of the American Chemical Society},
  title        = {Slow Internal Protein Dynamics from Water 1H Magnetic Relaxation Dispersion},
  url          = {http://dx.doi.org/10.1021/ja908144y},
  volume       = {131},
  year         = {2009},
}