Structure-Property relationship of S-layer protein assemblies at extremophilic archea bacteria

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Nature of the Work The long term objective of my research program is to investigate the extreme stability and unique properties of archaea Surface layer (S-layer) components for the ultimate purpose to engineer nano-devices in a variety of biotechnological fields. The research program combines Basic -and Applied Science with Bio-engineering and Synthetic Biology. We focus our attention on the structure-property relationship of the unique S-layer protein assembly from Staphylothermus marinus (S. marinus), an extremophillic archaea bacterium isolated from deep sea black smoker vents. S. marinus is a strict anaerobic sulfur reducing archaeon that utilizes peptides as a carbon source and grows at temperatures up to 98C. 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 proposed research will focus on investigating structural and mechanistic features of (i) the 3D-assembly mechanism of Tetrabrachion to form a quasi-crystalline S-layer, (ii) the molecular mechanisms of complex formation between Tetrabrachion and STABLE and (iii) the extreme stability of S-layer components as a foundation for bio-engineering and synthetic biology. All these studies involve a combination of structural, biophysical and synthetic approaches and offer undergraduate and graduate students a great variety of different skills in modern integrated research programs. Importance Since their discovery, archaea have been under intense scrutiny due to their unique adaptations to the extreme environments in which they thrive. 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. Outcome and Benefit The expected outcome is to obtain mechanistic and chemical information about the extreme stability of archaeal 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, remediation and catalytic nano-devices. Over the next 5 years, it is expected that 3-4 graduate students be engaged in this research program at any given time. Our findings will guide the design and analysis of artificial S-layer assemblies with great impact on Canada's biotech sector.