Subventions et des contributions :

Subvention ou bourse octroyée s'appliquant à plus d'un exercice financier. (2017-2018 à 2018-2019)

Importance
Since their discovery, hyperthermophilic archaea have been under intense scrutiny due to their unique adaptations to the extreme environments they thrive in. It is suggested that life has hyperthermophilic origins, and thus the study of these organisms provides insight into the biology of early life forms. In addition, understanding the molecular mechanisms of their adaptation to the extreme conditions (pH, Temperature, pressure, salinity, ionic strength) makes these microorganisms a perfect research tool for biotechnological developments.

Nature of the Work
The primary goal of the proposed research is to understand the structure-property relationship of the unique Surface layer (S-layer) protein assembly from Staphylothermus marinus ( S.marinus ), an extremophillic archea bacterium isolated from deep sea black smoker vents. S. marinus is a strict anaerobic sulfur reducing archaeon that utilizes peptides as carbon source and grows at temperatures up to 98°C. It has a proteinaceous S-layer consisting of elongated tetrabrachion units arranged in a 3D-network that forms a protein-protein heterocomplex with the hyperthermostable protease, called STABLE. As a consequence of its adaptation to the extreme conditions at the deep sea volcano, the S-layer proteins of S.marinus are characterized by an unusual stability. The research program will focus on structural and mechanistic features of (i) the extreme stability of S-layer components, (ii) the 3D-assembly mechanism of tetrabrachion to form a quasi-crystalline S-layer and (iii) the molecular mechanisms of complex formation between tetrabrachion and STABLE. Research will address questions that have arisen or have not been answered yet in the on-going structure-function studies. All these studies involve a combination of structural (X-ray crystallography in combination with SAXS), spectroscopic (UV-VIS, Fluorescence spectroscopy) in context with in-depth hydrodynamic (incl. DLS, SEC-MALS-RI and AUC) and microcalorimetric (incl. vpDSC, ITC and Microscale Thermophoresis) characterizations.

Outcome and Benefit
The overall outcome is to obtain mechanistic and chemical information about the extreme stability of archeal protein assemblies. Understanding the molecular basis of their unique adaptation, will open new perspectives on our understanding of the origin of life and will provide new insights into development of biotechnological applications in the broad fields of monitoring and remediation devices. Finally, not only will a more detailed mechanistic understanding of how S-layer assemblies are forming unique protection shields, but also applied science of great biotechnological importance will be achieved. It is expected that 2-3 papers will be published p.a. and 4-5 MSc/PhD students will graduate working in this research program.