3 items with the tag “homochirality

  • Project 7: Prebiotic Chemical Catalysis on Early Earth and Mars
    NAI 2013 Rensselaer Polytechnic Institute Annual Report

    The “RNA World” hypothesis is the current paradigm for the origins of terrestrial life. Our research is aimed at testing a key component of this paradigm: the efficiency with which RNA molecules form and grow under realistic conditions. We are studying abiotic production and polymerization of RNA by catalysis on montmorillonite clays. The catalytic efficiency of different montmorillonites are determined and compared, with the goal of determining which properties distinguish good catalysts from poor catalysts. We are also investigating the origin of montmorillonites, to test their probable availability on the early Earth and Mars, and the nature of catalytic activity that could have led to chiral selectivity on Earth.

    ROADMAP OBJECTIVES: 3.1 3.2
  • Molecular Biosignatures of Redox-Sensitive Bacteria and Hyperthermophiles
    NAI 2014 Massachusetts Institute of Technology Annual Report

    The Summons lab has been researching a range of molecular and isotopic phenomena aimed at shedding light on what controls Neoproterozoic ocean redox, evolutionary trends in the abundances of molecular fossils (biomarkers) and the enigmatic natural variability carbon isotopic compositions of organic and inorganic carbon at this time. Our studies of carotenoid pigment biomarkers for green and purple sulfur bacteria have revealed that they are ubiquitous in rock extracts of Proterozoic to Paleozoic age—implying that the shallow oceans became sulfidic more frequently than previously thought. Other projects focused on the biosynthesis of another important biomaker, the hopanoids, vesicles released from marine bacteria for interaction between cells and their environment, and the molecular signatures of microbial communities in hot springs in Yellowstone National Park.

    ROADMAP OBJECTIVES: 4.1 4.2 5.1 5.2 7.1
  • Project 3: The Origin of Homochirality
    NAI 2014 University of Illinois at Urbana-Champaign Annual Report

    A universal aspect of living systems on Earth is their homochirality: Life uses dextrorotary sugars and levorotary amino acids. The reasons for this are hotly debated and not close to being settled. However, the leading idea is that autocatalytic reactions grew exponentially fast at the origin of life, and whatever chiral symmetry breaking was accidentally present became amplified subsequently. We are calculating the way in which this can take place using statistical mechanics, and also trying to see how a uniform homochirality could be stable to spatial fluctuations.

    ROADMAP OBJECTIVES: 3.2 3.4 4.1 4.2 5.1 5.2 7.1 7.2