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Prebiotic synthesis of autocatalytic and self-replicating molecules from sugars as the primary carbon substrate
PI: Weber, Arthur
Summary: Our research objective is to understand and model the chemical processes on the primitive Earth that generated the first replicating molecules and cell-like microstructures involved in the origin of life. Our approach involves (a) investigation of a model origin-of-life process named the Sugar Model that is based on the reaction of sugars with ammonia, and (b) elucidation of the role of chemical constraints on the origin of life. The Sugar Model is a plausible “one-pot” prebiotic process that converts very simple substrates (formaldehyde and ammonia) into a variety of chemical building blocks, catalytic molecules, and energy-rich molecules essential to the origin of life. Recently, we showed that the reactions of the Sugar Model generate cell-like organic microspherules and “nucleic acid-like” molecules. Here we propose to investigate four aspects of the Sugar Model chemistry that are relevant to central questions about the origin of life: (1) the origin of biological asymmetry (homochirality) by examining the stereoselective synthesis of sugars by peptide catalysts, (2) the origin of autocatalytic protocells by incorporating catalytic groups into cell-like organic microspherules, (3) the origin of molecular replication by examining the prebiotic synthesis and properties of “nucleic acid-like” molecules from sugar-ammonia reactions, and (4) the origin of ammonia biosynthesis by investigating the ability of sugars to drive the synthesis of ammonia from nitrite (nitrate). In addition, to develop a better understanding of the chemical constraints that governed the origin of life we plan to estimate the reaction rates of nitrogen-containing organic molecules under mild aqueous conditions.
Our proposed study of prebiotic chemistry involved in the origin of life supports (a) NASA’s Strategic Sub-goal 3C: Advance scientific knowledge of the origin and history of the solar system . . .” which includes understanding “the origin and evolution of the Earth’s biosphere” and (b) NASA’s Astrobiology Program Element objective in Prebiotic Chemistry that seeks to determine “what chemical systems could have served as precursors of metabolic and replicating systems on Earth and elsewhere, including alternatives to the current DNA-RNA-protein basis for life.”
