Institut de Biologie StructuraleGrenoble / France

Contact person(s) related to this article / CARRE Lorenzo / FRANZETTI Bruno

Extremophilic systems as models for testing life in extra-terrestrial conditions

Principal Investigators : Bruno Franzetti, Eric Girard

Group members involved : Lorenzo Carré, Frank Gabel. Giuseppe Zaccaï

Astrophysicists have been seeking out life in extra-terrestrial environments for decades. Exoplanets keep being found over the years, yet the most promising places are located within our solar system : Europa and Enceladus subsurface oceans and Mars brines could have everything life needs according to terrestrial standards (liquid water, organic matter and energy source). However, the physical and chemical conditions of such environments could exceed terrestrial limits. For example, pressure at the bottom of Enceladus ocean may reach levels unknown to terrestrial organisms. As part of the “Origin Of Life” IDEX project, gathering astrophysicists chemists, and biologists, ELMA team uses enzymes from different types of extremophilic terrestrial organisms as models for testing limits of key biochemical processes. In particular, we are using the High-Pressure Platform and neutron spectrometry at ILL to determine how temperature, salinity and pressure can compensate each other and how far pressure can extend the range of conditions compatible with life processes. Our main model are DNA polymerases purified from hyperthermophilic barotolerant archaea. We also study other extremophilic proteins such as chaperones and proteases as well as living extremophilic cells.

Figure 1 : Life physico-chemical borders remaining to be experimentally tested in the context of planetary exploration (Planet image source : NASA).

Funding :

Collaborations :

  • D. Flament and G. Henneke. Ifremer, Laboratoire de Microbiologie des Environnements Extrêmes (LM2E), Brest.

Selected publications :

  • Jebbar M, Franzetti B, Girard E, Oger P. Microbial diversity and adaptation to high hydrostatic pressure in deep-sea hydrothermal vents prokaryotes. Extremophiles. 2015 ;19(4):721-40.
  • Vauclare P, Marty V, Fabiani E, Martinez N, Jasnin M, Gabel F, Zaccai, G and Franzetti, B. Molecular adaptation and salt stress response of Halobacterium salinarum cells revealed by neutron spectroscopy. Extremophiles. 2015 ;19(6):1099-107.
  • Rosenbaum E, Gabel F, Durá MA, Finet S, Cléry-Barraud C, Masson P and Franzetti B Effects of hydrostatic pressure on the quaternary structure and enzymatic activity of a large peptidase complex from Pyrococcus horikoshii. Archives of Biochemistry and Biophysics (2012) 517 (2) : 104–110
  • Tehei M, Franzetti B, Wood K, Gabel F, Fabiani E, Jasnin M, et al. Neutron scattering reveals extremely slow cell water in a Dead Sea organism. Proc Natl Acad Sci U S A. 2007 ;104(3):766-71.
  • Tehei M, Franzetti B, Maurel MC, Vergne J, Hountondji C, Zaccai G. The search for traces of life : the protective effect of salt on biological macromolecules. Extremophiles. 2002 ;6(5):427-30.
  • Girard E, Marchal S, Perez J, Finet S, Kahn R, Fourme R, Marassio G, Dhaussy AC, Prange T, Giffard M, Dulin F, Bonnete F, Lange R, Abraini JH, Mezouar M and Colloc’h N. Structure-function perturbation and dissociation of tetrameric urate oxidase by high hydrostatic pressure. Biophysical Journal (2010) 98(10) : 2365-237.