Article: article from journal or magazin.
Thermodynamic studies of binding proteins: effects of temperature variations on substrate binding and conformation of the leucine-isoleucine-valine binding protein of Escherichia coli
The behaviour of the Leucine isoleucine Valine binding protein of Escherichia coli as a function of temperature has been examined. Substrate binding measurements showed a temperature dependence of the leucine-isoleucine-valine binding protein leucine complex formation constants. The protein-substrate complex was completely dissociated beyond 70 degrees C. In the range 5-65 degrees C the protein remained active but Van't Hoff's plots indicated changes of the reaction thermodynamic parameters. Large negative delta Cp values (--2.25 kJ mole-1 K-1 between 5 and 40 degrees C and--9.40 above 40 degrees C) indicate important substrate induced modifications of the protein conformation. Scanning calorimetry of the leucine isoleucine valine binding protein before and after addition of leucine was also performed. Two thermal events were recorded when the protein was substratefree and only one, at a higher temperature and more important, when the substrate was added. The results of these two approaches were in agreement in that both methods suggested a binding dependent conformational change of the protein which resulted in a greater stability of its structure.
*Bacterial Proteins Calorimetry, Differential Scanning *Carrier Proteins Chemistry, Physical Escherichia coli *Escherichia coli Proteins Mathematics *Oligopeptides Protein Conformation *Temperature
Web of science
Last modification date