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 destabilize the native state at high pressure. 2003 Elsevier Science B.V. All rights reserved.