Water and protein dynamics on a nanometer scale were measured by quasi-elastic neutron scattering in the piezophile archaeon Thermococcus barophilus and the closely related pressure-sensitive Thermococcus kodakarensis, at 0.1 and 40 MPa. We show that cells of the pressure sensitive organism exhibit higher intrinsic stability. Both the hydration water dynamics and the fast protein and lipid dynamics are reduced under pressure. In contrast, the proteome of T. barophilus is more pressure sensitive than that of T. kodakarensis. The diffusion coefficient of hydration water is reduced, while the fast protein and lipid dynamics are slightly enhanced with increasing pressure. These findings show that the coupling between hydration water and cellular constituents might not be simply a master-slave relationship. We propose that the high flexibility of the T. barophilus proteome associated with reduced hydration water may be the keys to the molecular adaptation of the cells to high hydrostatic pressure.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: We are gratefully acknowledging the help of B. Frick for the measurement on IN16 and of M.M. Koza for the measurement on IN6, the ILL for allocation of beam time and the financing of the Agence Nationale de la Recherche (ANR; project number ANR 2010 BLAN 1725 01 Living deep).