Protein unfolding pressure induced

Turning now to the chapters in this volume, a variety of complementary techniques and approaches have been used to characterize peptide and protein unfolding induced by temperature, pressure, and solvent. Our goal has been to assemble these complementary views within a single volume in order to develop a more complete picture of denatured peptides and proteins. The unifying observation in common to all chapters is the detection of preferred backbone conformations in experimentally accessible unfolded states. 

Because the molar volume of an unfolded protein is less than that of the native state, increasing pressure leads to denaturation (Gross and Jaenicke, 1994). Royer and co-workers have employed high-pressure SAXS to monitor the pressure-induced unfolding of Snase. They find that the unfolded ensemble achieves a pressure-independent Rg of... 

It is of particular interest to note that the temperature dependence of the pressure-induced unfolding and the urea-induced unfolding of proteins at ambient pressure give rise to negative activation energies, i.e. these processes go faster at lower temperatures. Bridgman already noted this effect and found it quite unexpected [1]. 

These mechanisms are consistent with the differences that have been observed between the temperature and pressure induced unfolding of proteins with various experimental approaches. 

Certain pressure-induced unfolding transitions are known to occur slowly. The time required for conformational equilibration after the application of pressure has been found to depend on the protein itself, on the temperature, and on other environmental parameters. Therefore, as a general rule, samples should be allowed to equilibrate under pressure for 12 h prior to electrophoresis. 

Pressure-induced unfolding In the relationship for pressure, P, induced unfolding of proteins, AG° is again the value of the free energy change at 1 atmosphere pressure and A F = Vu -Vn is the difference in volume... 

Approaches taken to induce protein unfolding by MD simulation have involved the use of high temperature, chemical denaturants, or high pressure.Commensurate with their common use in experimental... 

There are several reasons to measure the effect of pressure on a wide variety of thermodynamic systems. Perhaps the most important argument is that one can separate the effects of volume and thermal energy changes, which appear simultaneously in temperature experiments . Moreover, high pressure can induce unfolding of protein in a different way from thermal denaturation. The pressure studies have considerably increased in the last decades" . 

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