[Soft Matter Café] Unravelling the mechanisms of adaptation to high pressure in proteins

The adaptation of proteins to high pressure is still an open debate, but understanding it could shed light on the origins of life, lead to a better understanding of protein dynamics, and deliver new tools to engineer pressure-resistant enzymes for biotechnological purposes. While the thermodynamic and dynamical properties of model proteins under pressure have been extensively studied, the evolutionary aspects of their adaptation are still unclear.
Disentangling the contributions of pressure adaptation from those of another adaptation, such as high or low temperature, is a difficult task and, in fact, genomic studies were unable to determine a clear pattern among the order of Thermococcales.
Recent experiments by our group focused on whole cells of two closely related species (Thermococcus barophilus, Tba, and Thermococcus kodakarensis, Tko) that grow at the same optimal temperature (85°C) but differ only for the optimum pressure (400 bar for Tba, 1 bar for Tko), and they highlighted the differences in the dynamics of the two organisms’ proteomes.
To take this investigation to the molecular level, we studied the Phosphomannose Isomerase and the Ribosomal protein S24e from the two organisms with Elastic and Quasi-elastic Incoherent Neutron Scattering, 2-D NMR Spectroscopy and X-ray crystallography. Our results evidence that the substitutions of amino acids enhancing pressure stability are those in the hydrophobic core, which eliminate cavities, and those on the surface, which modulate the interaction of the proteins with the surrounding water layer and give them the right flexibility to perform their function under high pressure.

About the speaker:  Judith Peters graduated in Physics at the University Joseph Fourier Grenoble 1 and received her PhD in Theoretical Physics in 1988. She then had a post-doctoral position at the University of Heidelberg working on molecular dynamics simulations. After one year as exchange scientist at the University of St. Petersburg, 7 years as assistant professor at the University of Applied Sciences in Berlin and 10 years as scientist at the Helmholtz Zentrum Berlin, she holds now a professorship of Physics at Université Grenoble Alpes. Her research interests comprise dynamical studies of biosystems by neutron scattering techniques, particularly under high pressure conditions.