TY - JOUR
T1 - Hydration analysis of Pseudomonas aeruginosa cytochrome c551 upon acid unfolding by dielectric relaxation spectroscopy
AU - Wazawa, Tetsuichi
AU - Miyazaki, Takashi
AU - Sambongi, Yoshihiro
AU - Suzuki, Makoto
PY - 2010/10
Y1 - 2010/10
N2 - Dielectric relaxation (DR) study was performed to reveal the hydration change of Pseudomonas aeruginosa ferric cytochrome c551 (PA c551) in dilute aqueous solutions upon the acid unfolding which undergoes a two-state transition. The DR spectrum of a small spherical region containing a PA c551 molecule and its surrounding water shell was derived from the solution and solvent spectra by dielectric mixture theories. The derived spectrum was well-fitted with a sum of a Debye relaxation component (C1) with a DR frequency around 4.7. GHz and the bulk solvent component (CB). Upon acid unfolding, the DR amplitude of CB decreased with decreasing pH in an inverse manner to that of C1, while the total DR amplitude was almost constant. It indicates that C1 is due to the hydration water of PA c551. Little change in the DR frequency of C1 and a 1.7-fold increase in hydration number were observed.
AB - Dielectric relaxation (DR) study was performed to reveal the hydration change of Pseudomonas aeruginosa ferric cytochrome c551 (PA c551) in dilute aqueous solutions upon the acid unfolding which undergoes a two-state transition. The DR spectrum of a small spherical region containing a PA c551 molecule and its surrounding water shell was derived from the solution and solvent spectra by dielectric mixture theories. The derived spectrum was well-fitted with a sum of a Debye relaxation component (C1) with a DR frequency around 4.7. GHz and the bulk solvent component (CB). Upon acid unfolding, the DR amplitude of CB decreased with decreasing pH in an inverse manner to that of C1, while the total DR amplitude was almost constant. It indicates that C1 is due to the hydration water of PA c551. Little change in the DR frequency of C1 and a 1.7-fold increase in hydration number were observed.
KW - Acid denaturation
KW - Constrained water
KW - Debye relaxation
KW - Dielectric dispersion
KW - Loosely-bound water
KW - Two-state transition
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U2 - 10.1016/j.bpc.2010.06.008
DO - 10.1016/j.bpc.2010.06.008
M3 - Article
C2 - 20630646
AN - SCOPUS:77955842577
VL - 151
SP - 160
EP - 169
JO - Biophysical Chemistry
JF - Biophysical Chemistry
SN - 0301-4622
IS - 3
ER -