Origins Postdoctoral Fellow - Dept. of Earth & Planetary Sciences (Pearson Lab)
One of the fundamental processes of the origin of life is the need to separate biochemical reactions from the environment to build the first cells. Under the extreme conditions of early Earth, the need for membrane stability would have been paramount. The domain of Archaea exists in a broad range of habitats on Earth, and many extremophilic species are near the root of the phylogenetic tree of life. Their capabilities to survive a wide range of temperature, pH, pressure, and ionic strength make them highly notable to understand the evolution of early life. Membrane lipids of Archaea are highly stable and distinguished from those of Bacteria and Eukarya by several features. Archaeal lipids are composed of saturated isoprenoid chains linked to the glycerol molecule at the sn-2 and 3-positions by ether instead of ester bonds, and Archaea form glycerol dialkyl glycerol tetraether (GDGT) lipids in addition to diether lipids. A nearly complete, plausible pathway for the biosynthesis of the diether lipids is proposed, but little is known about the specific step of tetraether (GDGT) formation.
The question is how can this step be evaluated? Which enzyme is responsible for the last step of archaeal lipid synthesis or how can it be identified?
I will introduce a method that has been frequently used in medical drug characterization: Activity Based Protein Profiling (ABPP) and will demonstrate how this powerful method can be applied to the question how the first microorganisms developed their tough membrane to withstand the harsh conditions of early Earth.