Protein dynamics: hydration and cavities

Abstract

The temperature-pressure behavior of proteins seems to be unique among the biological macromolecules. Thermodynamic as well as kinetic data show the typical elliptical stability diagram. This may be extended by assuming that the unfolded state gives rise to volume and enthalpy-driven liquid-liquid transitions. A molecular interpretation follows from the temperature and the pressure dependence of the hydration and cavities. We suggest that positron annihilation spectroscopy can provide additional quantitative evidence for the contributions of cavities to the dynamics of proteins. Only mature amyloid fibrils that form from unfolded proteins are very resistant to pressure treatment.

High-Pressure Potato Starch Granule Gelatinization: Synchrotron Radiation Micro-SAXS/WAXS Using a Diamond Anvil Cell

“…At this stage the external granule shape is still intact. The data support a model suggesting an initial solvation step followed by a helix−coil transition of the molecular chains. , …”

“…The data support a model suggesting an initial solvation step followed by a helix-coil transition of the molecular chains. 15,42 The experiments show that it is possible to collect SAXS/ WAXS data up to about 1000 MPa in a DAC with a 1 µm synchrotron radiation beam from biopolymer samples. This is an interesting possibility for biopolymer sample quantities, which are only available in small volumes or have to be investigated with high spatial resolution.…”

Biomolecules under Pressure: Phase Diagrams, Volume Changes, and High Pressure Spectroscopic Techniques

“…Unfortunately, it is very difficult to directly measure the above terms separately. Both the cavities and the hydration can play determining roles in the case of pressure-induced conformational changes, depending on the molecules in question, although the determining role of the cavities seems nowadays to be more accepted [ 14 , 26 , 27 , 28 , 29 ].…”

Negative volume changes of human G-quadruplexes at unfolding

“…The increased density and consequently the reduced volume of this solvent layer appears as a negative contribution to the volume of the solute molecule. In the case of proteins, this hydration layer increases upon unfolding [24,25,26], while in the case of GQs, the hydration shell of the released ions may also play a role [27].…”