Blue Marble Space

Chiral Molecules Are Likely to Have Been Important Early in the History of Life on Earth Because Biological Polymers (e.g. Proteins and Nucleic Acids) Are Homochiral: Their Monomers Consist of Only One of the Two Possible Enantiomers. However Naturally Occurringcommon Abiotic Synthetic Processes That Take Place Today or in the Early Solar System Were Generally Assumed to Produce Only Racemic Mixtures Which Are Equal Amounts of Enantiomers. the Fact That Life on Earth Has Strict Homochirality Might Imply That Very Early There Were Ubiquitous and Determining Physical Forces That Directed the Direction of Enantiomer Excesses in Organic Biopolymers (e.g. They Preferentially Aided the Synthesis of "L" Amino Acids and "D" Sugars). However the Overwhelming Majority of Experiments That Attempt to Create Enantiomer Excesses Begin With Pre-made (pre-synthesized) Pairs of Enantiomers E.g. the Slight Preferential Destruction of One Enantiomer by Right or Left Circularly Polarized Light (flores Bonner and Massey 1977 Jacs). Likewise Research on Combined Magnetism Plus Radiation (photo-magnetic) Effects Has So Far Been Applied (mostly Theoretically) to Inorganic Complexes (also Assuming Pre-existing Enantiomers) Resulting in the Production of Very Small (~ 10-4) Excesses Between Enantiomers (rikken and Raupach 2000 Nature). However We Propose That Photo-magnetic Effects During Actual Synthetic Reactions (formose-like Reactions) Might Be Capable of Producing Significant Enantiomer Excesses. the Products of These Reactions Would Be Biologically Relevant Organic Compounds: Such Reactions May Have Been Significant on the Early Earth and Other Solar System Bodies. Preliminary Results Give Hints of This Possibility. This Proposed Work Would Utilize Laboratory Simulations Organic Analyses and Computational Chemistry (magnetic Effects on Organic Compounds) to Investigate the Scenario That Radiation and Magnetism May Have Been Involved in the Early Generation of Enantiomer Excesses Likely Required for Subsequent Life. the Major Analytical Techniques Will Include Chiral Analyses by Gas Chromatographymass Spectrometry (GC-MS) Liquid Chromatography-ms and Polarimetry. Equipment for Simulation Experiments Will Include Lamps and Magnets of Various Intensities. the Goals of This Proposal Are Highly Relevant to Those of Nasa and the Exobiology Program. One of the Emphases of the Exobiology Program Is "prebiotic Evolution": ..."a Major Objective Is Determining What Chemical Systems Could Have Served as Precursors of Metabolic and Replicating Systems on Earth and Elsewhere ...". It Is Very Possible That Prebiotic Homochirality or at Least Significant Enantiomer Excesses Might Have Been a Necessary Precursor of Nucleic Acids. in Laboratory Model Systems Nucleic Acid Polymers Do Not Form to a Significant Extent If Their Monomer Building Blocks Are Racemic E.g. G. Joyce Et Al. 1984 Pnas. Such Results Might Imply That Replicating Molecules (as We Know Them) Required Near-homochiral Building Blocks. Our Proposed Research May at Least Reveal a Possible Mechanism of Creating Enantiomer Excesses in Such Precursors During the Actual Synthesis of Compounds From Realistic and Widely Available Prebiotic Molecules.