High pressure - unfolding of myoglobin studied by dynamic neutron scattering

Globular proteins tend to unfold in response to the application of hydrostatic pressure typically above 3 kbar. This process is driven by a decrease in volume, which may occur either by releasing intra-molecular voids or by contraction of the solvent near the newly exposed protein surface. The latter involves changes in structure of the protein-solvent network. By dynamic neutron scattering we probe the pressure evolution of protein-solvent bonds. At the unfolding transition, we observe a reduction of the structural inter-conversion rates, while the fluctuation amplitudes remain essentially unaffected. This result suggests that enhanced protein-solvent interactions in the unfolded form may de-stabilize the native state at high pressure. (C) 2003 Elsevier Science B.V. All rights reserved.