Dresden 2006 – scientific programme
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CPP: Chemische Physik und Polymerphysik
CPP 28: Biological Systems
CPP 28.4: Talk
Friday, March 31, 2006, 11:15–11:30, ZEU Lich
Thermodynamic stability of proteins — •Johannes Wiedersich1, Simone Köhler1, Josef Friedrich1, and Arne Skerra2 — 1Physikdepartment E14, Lehrstuhl für Physik Weihenstephan, TU München, Germany — 2Lehrstuhl für Biologische Chemie, TU München
The folding of proteins shows a complex scenario, the details of which are not yet fully understood. One important aspect concerns the stability of proteins. By means of fluorescence spectroscopy, we study the stability of the anticallin FluA–fluorescein complex, a small protein specifically taylored to bind the fluorophore fluorescein, as a function of pressure and temperature.
Although it is known that protein folding follows a complex path, the temperature and pressure denaturation of FluA is well described by a simple two-state model. The observed elliptic shape of the p-T phase diagram implies that—despite the complexity of protein folding—the thermodynamic parameters (namely specific heat capacity, compressibility, thermal expansion) are rather well defined and do not significantly depend on pressure and temperature. We discuss the implications of our findings on the understanding of generic features of the protein folding transition, especially on its similarities to the glass transition.