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Trifluoroethanol-induced beta -> alpha transition in beta-lactoglobulin: hydration and cosolvent binding studied by 2H, 17O, and 19F magnetic relaxation dispersion.

Kumar, S; Modig, Kristofer LU and Halle, Bertil LU (2003) In Biochemistry 42(46). p.13708-13716
Abstract
Alcohols, such as 2,2,2-trifluoroethanol (TFE), have been shown to induce a cooperative transition to an open helical structure in many proteins, but the underlying molecular mechanism has not been identified. Here, we employ the technique of magnetic relaxation dispersion (MRD) to study the TFE-induced transition of -lactoglobulin at pH 2.4. Unlike traditional techniques that focus on protein secondary structure, the MRD method directly monitors the solvent, providing quantitative information about preferential solvation and solvent penetration and about the overall size and structural integrity of the protein. In this multinuclear MRD study, we use the 2H and 17O resonances to examine hydration and the 19F resonance to study TFE. The... (More)
Alcohols, such as 2,2,2-trifluoroethanol (TFE), have been shown to induce a cooperative transition to an open helical structure in many proteins, but the underlying molecular mechanism has not been identified. Here, we employ the technique of magnetic relaxation dispersion (MRD) to study the TFE-induced transition of -lactoglobulin at pH 2.4. Unlike traditional techniques that focus on protein secondary structure, the MRD method directly monitors the solvent, providing quantitative information about preferential solvation and solvent penetration and about the overall size and structural integrity of the protein. In this multinuclear MRD study, we use the 2H and 17O resonances to examine hydration and the 19F resonance to study TFE. The transformation from the native to the helical state via an intermediate state at 300 K is found to be accompanied by a progressive expansion of the protein and loss of specific long-lived hydration sites. The observation of 17O and 19F dispersions from the helical state shows that water and TFE penetrate the protein. The MRD data indicate a strong accumulation of TFE at the surface as well as in the interior of the protein. At 277 K, BLG is much less affected by TFE, remaining in the native state at 16% TFE, but adopting a nonnative structure at 30% TFE. This nonnative structure is not penetrated by long-lived water molecules. The implications of these findings for the mechanism of TFE-induced structural transformations are discussed. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Biochemistry
volume
42
issue
46
pages
13708 - 13716
publisher
The American Chemical Society
external identifiers
  • wos:000186695400038
  • scopus:0344391914
ISSN
0006-2960
DOI
10.1021/bi035330l
language
English
LU publication?
yes
id
0feeb75c-c29b-406b-8ce7-379e3e60a284 (old id 128064)
date added to LUP
2007-06-29 11:53:02
date last changed
2018-10-03 10:52:24
@article{0feeb75c-c29b-406b-8ce7-379e3e60a284,
  abstract     = {Alcohols, such as 2,2,2-trifluoroethanol (TFE), have been shown to induce a cooperative transition to an open helical structure in many proteins, but the underlying molecular mechanism has not been identified. Here, we employ the technique of magnetic relaxation dispersion (MRD) to study the TFE-induced transition of -lactoglobulin at pH 2.4. Unlike traditional techniques that focus on protein secondary structure, the MRD method directly monitors the solvent, providing quantitative information about preferential solvation and solvent penetration and about the overall size and structural integrity of the protein. In this multinuclear MRD study, we use the 2H and 17O resonances to examine hydration and the 19F resonance to study TFE. The transformation from the native to the helical state via an intermediate state at 300 K is found to be accompanied by a progressive expansion of the protein and loss of specific long-lived hydration sites. The observation of 17O and 19F dispersions from the helical state shows that water and TFE penetrate the protein. The MRD data indicate a strong accumulation of TFE at the surface as well as in the interior of the protein. At 277 K, BLG is much less affected by TFE, remaining in the native state at 16% TFE, but adopting a nonnative structure at 30% TFE. This nonnative structure is not penetrated by long-lived water molecules. The implications of these findings for the mechanism of TFE-induced structural transformations are discussed.},
  author       = {Kumar, S and Modig, Kristofer and Halle, Bertil},
  issn         = {0006-2960},
  language     = {eng},
  number       = {46},
  pages        = {13708--13716},
  publisher    = {The American Chemical Society},
  series       = {Biochemistry},
  title        = {Trifluoroethanol-induced beta -> alpha transition in beta-lactoglobulin: hydration and cosolvent binding studied by 2H, 17O, and 19F magnetic relaxation dispersion.},
  url          = {http://dx.doi.org/10.1021/bi035330l},
  volume       = {42},
  year         = {2003},
}