Volumetric and spectroscopic characterizations of glucose-hexokinase association.
The binding of D-glucose to hexokinase PII at 25 degrees C and pH 8.7 has been investigated by a combination of ultrasonic velocimetry, high precision densimetry, and fluorescence spectroscopy. The binding of glucose to the enzyme results in significant dehydration of the two interacting molecules, while the intrinsic coefficient of adiabatic compressibility of hexokinase slightly decreases. Glucose-hexokinase association is an entropy-driven process. The favorable change in entropy results from compensation between two large contributions. The binding-induced increase in hydrational entropy slightly prevails over the decrease in the configurational entropy of the enzyme. Taken together, our results emphasize the crucial role of water in modulating the energetics of protein recognition.
Filfil
Rana
R
Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, 19 Russell Street, Toronto, ON, Canada M5S 2S2.
Chalikian
Tigran V
TV
D003681:Dehydration; D005947:Glucose / Q000737:chemistry / Q000378:metabolism*; D006593:Hexokinase / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D013050:Spectrometry, Fluorescence; D013816:Thermodynamics; D014465:Ultrasonics; D014867:Water / Q000737:chemistry; D015003:Yeasts / Q000201:enzymology
D014867:Water; D006593:Hexokinase; D005947:Glucose