Premium
Pressure effect on denaturant‐induced unfolding of hen egg white lysozyme
Author(s) -
Sasahara Kenji,
Sakurai Masao,
Nitta Katsutoshi
Publication year - 2001
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/prot.1083
Subject(s) - cooperativity , lysozyme , hydrostatic pressure , chemistry , gibbs free energy , equilibrium unfolding , thermodynamics , crystallography , native state , hydrostatic equilibrium , circular dichroism , biochemistry , physics , quantum mechanics
The influence of hydrostatic pressure (≤100 MPa) on denaturant‐induced unfolding of hen egg white lysozyme was investigated by means of ultraviolet spectroscopy at various temperatures. Assuming a two‐state transition model, the dependence of Gibbs free‐energy change of unfolding on the denaturant concentration was calculated. Under applied hydrostatic pressure, these data were interpreted as suggesting that a two‐state model is not applicable in a restricted temperature range; the dominant effect of hydrostatic pressure is to affect the cooperativity in protein unfolding due to a chemical equilibrium shift in the direction of the reduction in the system volume. The deviation from the two‐state transition model appears to be rationalized by assuming that applied pressure induces an intermediate conformation between the native and unfolded states of the protein. The implication of the thermodynamic stability of protein under pressure was discussed. Proteins 2001;44:180–187. © 2001 Wiley‐Liss, Inc.