Water contributes actively to the rapid crossing of a protein unfolding barrier.

Détails

ID Serval
serval:BIB_988DA6605886
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Water contributes actively to the rapid crossing of a protein unfolding barrier.
Périodique
Journal of Molecular Biology
Auteur(s)
Jacob M.H., Saudan C., Holtermann G., Martin A., Perl D., Merbach A.E., Schmid F.X.
ISSN
0022-2836
Statut éditorial
Publié
Date de publication
2002
Peer-reviewed
Oui
Volume
318
Numéro
3
Pages
837-845
Langue
anglais
Résumé
The cold-shock protein CspB folds rapidly in a N <= => U two-state reaction via a transition state that is about 90% native in its interactions with denaturants and water. This suggested that the energy barrier to unfolding is overcome by processes occurring in the protein itself, rather than in the solvent. Nevertheless, CspB unfolding depends on the solvent viscosity. We determined the activation volumes of unfolding and refolding by pressure-jump and high-pressure stopped-flow techniques in the presence of various denaturants. The results obtained by these methods agree well. The activation volume of unfolding is positive (Delta V(++)(NU)=16(+/-4) ml/mol) and virtually independent of the nature and the concentration of the denaturant. We suggest that in the transition state the protein is expanded and water molecules start to invade the hydrophobic core. They have, however, not yet established favorable interactions to compensate for the loss of intra-protein interactions. The activation volume of refolding is positive as well (Delta V(++)(NU)=53(+/-6) ml/mol) and, above 3 M urea, independent of the concentration of the denaturant. At low concentrations of urea or guanidinium thiocyanate, Delta V(++)(UN) decreases significantly, suggesting that compact unfolded forms become populated under these conditions.
Mots-clé
Bacillus subtilis/chemistry, Bacterial Proteins/chemistry, Guanidines, Kinetics, Pressure, Protein Denaturation, Protein Folding, Recombinant Proteins/chemistry, Thermodynamics, Thiocyanates, Urea, Water/chemistry
Pubmed
Web of science
Création de la notice
19/05/2008 12:00
Dernière modification de la notice
20/08/2019 16:00
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