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Pressure-induced protein unfolding in the ternary system AOT-octane-water is different from that in bulk water

Meersman, F; Dirix, C; Shipovskov, Stepan LU ; Klyachko, N L and Heremans, K (2005) In Langmuir 21(8). p.3599-3604
Abstract
In a cellular environment, the presence of macromolecular cosolutes and membrane interfaces can influence the folding-unfolding behavior of proteins. Here we report on the pressure stability of alpha-chymotrypsin in the ternary system bis(2-ethylhexyl)sodium sulfosuccinate-octane-water using FTIR spectroscopy. The ternary system forms anionic reverse micelles which mimic cellular conditions. We find that inclusion of a single protein molecule in a reverse micelle does not alter its conformation. When pressurized in bulk water, alpha-chymotrypsin unfolds at 750 MPa into a partially unfolded structure. In contrast, in the ternary system, the same pressure increase induces a random coil-like unfolded state, which collapses into an amorphous... (More)
In a cellular environment, the presence of macromolecular cosolutes and membrane interfaces can influence the folding-unfolding behavior of proteins. Here we report on the pressure stability of alpha-chymotrypsin in the ternary system bis(2-ethylhexyl)sodium sulfosuccinate-octane-water using FTIR spectroscopy. The ternary system forms anionic reverse micelles which mimic cellular conditions. We find that inclusion of a single protein molecule in a reverse micelle does not alter its conformation. When pressurized in bulk water, alpha-chymotrypsin unfolds at 750 MPa into a partially unfolded structure. In contrast, in the ternary system, the same pressure increase induces a random coil-like unfolded state, which collapses into an amorphous aggregate during the decompression phase. It is suggested that the unfolding pathway is different in a cell-mimicking environment due to the combined effect of multiple factors, including confinement. A phase transition of the reverse micellar to the lamellar phase is thought to be essential to provide the conditions required for unfolding and aggregation, though the unfolding is not a direct result of the phase transition. Our observations therefore suggest that membranes may cause the formation of alternative conformations that are more susceptible to aggregation. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Langmuir
volume
21
issue
8
pages
3599 - 3604
publisher
The American Chemical Society
external identifiers
  • wos:000228218700057
  • pmid:15807607
  • scopus:17444382363
ISSN
0743-7463
DOI
10.1021/la0470481
language
English
LU publication?
yes
id
364049e3-d7a2-461b-8e2c-9c0f95ab96ee (old id 152263)
date added to LUP
2007-07-09 15:55:13
date last changed
2017-03-12 03:34:00
@article{364049e3-d7a2-461b-8e2c-9c0f95ab96ee,
  abstract     = {In a cellular environment, the presence of macromolecular cosolutes and membrane interfaces can influence the folding-unfolding behavior of proteins. Here we report on the pressure stability of alpha-chymotrypsin in the ternary system bis(2-ethylhexyl)sodium sulfosuccinate-octane-water using FTIR spectroscopy. The ternary system forms anionic reverse micelles which mimic cellular conditions. We find that inclusion of a single protein molecule in a reverse micelle does not alter its conformation. When pressurized in bulk water, alpha-chymotrypsin unfolds at 750 MPa into a partially unfolded structure. In contrast, in the ternary system, the same pressure increase induces a random coil-like unfolded state, which collapses into an amorphous aggregate during the decompression phase. It is suggested that the unfolding pathway is different in a cell-mimicking environment due to the combined effect of multiple factors, including confinement. A phase transition of the reverse micellar to the lamellar phase is thought to be essential to provide the conditions required for unfolding and aggregation, though the unfolding is not a direct result of the phase transition. Our observations therefore suggest that membranes may cause the formation of alternative conformations that are more susceptible to aggregation.},
  author       = {Meersman, F and Dirix, C and Shipovskov, Stepan and Klyachko, N L and Heremans, K},
  issn         = {0743-7463},
  language     = {eng},
  number       = {8},
  pages        = {3599--3604},
  publisher    = {The American Chemical Society},
  series       = {Langmuir},
  title        = {Pressure-induced protein unfolding in the ternary system AOT-octane-water is different from that in bulk water},
  url          = {http://dx.doi.org/10.1021/la0470481},
  volume       = {21},
  year         = {2005},
}