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High water mobility on the ice-binding surface of a hyperactive antifreeze protein.

Modig, Kristofer LU ; Qvist, Johan LU ; Marshall, Christopher B; Davies, Peter L and Halle, Bertil LU (2010) In Physical chemistry chemical physics : PCCP 12(Online 29th July 2010). p.10189-10197
Abstract
Antifreeze proteins (AFPs) prevent uncontrolled ice formation in organisms exposed to subzero temperatures by binding irreversibly to specific planes of nascent ice crystals. To understand the thermodynamic driving forces and kinetic mechanism of AFP activity, it is necessary to characterize the hydration behavior of these proteins in solution. With this aim, we have studied the hyperactive insect AFP from Tenebrio molitor (TmAFP) with the (17)O magnetic relaxation dispersion (MRD) method, which selectively monitors the rotational motion and exchange kinetics of water molecules on picosecond-microsecond time scales. The global hydration behavior of TmAFP is found to be similar to non-antifreeze proteins, with no evidence of ice-like or... (More)
Antifreeze proteins (AFPs) prevent uncontrolled ice formation in organisms exposed to subzero temperatures by binding irreversibly to specific planes of nascent ice crystals. To understand the thermodynamic driving forces and kinetic mechanism of AFP activity, it is necessary to characterize the hydration behavior of these proteins in solution. With this aim, we have studied the hyperactive insect AFP from Tenebrio molitor (TmAFP) with the (17)O magnetic relaxation dispersion (MRD) method, which selectively monitors the rotational motion and exchange kinetics of water molecules on picosecond-microsecond time scales. The global hydration behavior of TmAFP is found to be similar to non-antifreeze proteins, with no evidence of ice-like or long-ranged modifications of the solvent. However, two sets of structural water molecules, located within the core and on the ice-binding face in the crystal structure of TmAFP, may have functional significance. We find that 2 of the 5 internal water molecules exchange with a residence time of 8 +/- 1 mus at 300 K and a large activation energy of approximately 50 kJ mol(-1), reflecting intermittent large-scale conformational fluctuations in this exceptionally dense and rigid protein. Six water molecules arrayed with ice-like spacing in the central trough on the ice-binding face exchange with bulk water on a sub-nanosecond time scale. The combination of high order and fast exchange may allow these water molecules to contribute entropically to the ice-binding affinity without limiting the absorption rate. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical chemistry chemical physics : PCCP
volume
12
issue
Online 29th July 2010
pages
10189 - 10197
publisher
Royal Society of Chemistry
external identifiers
  • wos:000281352300006
  • pmid:20668761
  • scopus:77957999861
ISSN
1463-9084
DOI
10.1039/c002970j
language
English
LU publication?
yes
id
4b77371e-9a7a-42fe-93b4-7f20ce1c8d8e (old id 1644451)
date added to LUP
2010-08-27 12:45:33
date last changed
2018-06-17 04:17:32
@article{4b77371e-9a7a-42fe-93b4-7f20ce1c8d8e,
  abstract     = {Antifreeze proteins (AFPs) prevent uncontrolled ice formation in organisms exposed to subzero temperatures by binding irreversibly to specific planes of nascent ice crystals. To understand the thermodynamic driving forces and kinetic mechanism of AFP activity, it is necessary to characterize the hydration behavior of these proteins in solution. With this aim, we have studied the hyperactive insect AFP from Tenebrio molitor (TmAFP) with the (17)O magnetic relaxation dispersion (MRD) method, which selectively monitors the rotational motion and exchange kinetics of water molecules on picosecond-microsecond time scales. The global hydration behavior of TmAFP is found to be similar to non-antifreeze proteins, with no evidence of ice-like or long-ranged modifications of the solvent. However, two sets of structural water molecules, located within the core and on the ice-binding face in the crystal structure of TmAFP, may have functional significance. We find that 2 of the 5 internal water molecules exchange with a residence time of 8 +/- 1 mus at 300 K and a large activation energy of approximately 50 kJ mol(-1), reflecting intermittent large-scale conformational fluctuations in this exceptionally dense and rigid protein. Six water molecules arrayed with ice-like spacing in the central trough on the ice-binding face exchange with bulk water on a sub-nanosecond time scale. The combination of high order and fast exchange may allow these water molecules to contribute entropically to the ice-binding affinity without limiting the absorption rate.},
  author       = {Modig, Kristofer and Qvist, Johan and Marshall, Christopher B and Davies, Peter L and Halle, Bertil},
  issn         = {1463-9084},
  language     = {eng},
  number       = {Online 29th July 2010},
  pages        = {10189--10197},
  publisher    = {Royal Society of Chemistry},
  series       = {Physical chemistry chemical physics : PCCP},
  title        = {High water mobility on the ice-binding surface of a hyperactive antifreeze protein.},
  url          = {http://dx.doi.org/10.1039/c002970j},
  volume       = {12},
  year         = {2010},
}