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2001 Annual Science Report

Scripps Research Institute Reporting  |  JUL 2000 – JUN 2001

Self-Reproducing (SL) Molecular Systems and Darwinian Chemistry - Switzer's Laboratory

4 Institutions
3 Teams
0 Publications
0 Field Sites
Field Sites

Project Progress

Self-Reproducing (SL) Molecular Systems and Darwinian Chemistry (dm)

The primary goal of the Switzer laboratory is to synthesize Alternative Nucleic Acids (ANAs) to attempt the optimization of polymer structure subject to the constraints of prebiotic availability, template-directed reproduction, replication conservative mutation, and fitness. We have identified ANAs by taking small steps in “structure-space” away from RNA (the best model for a molecule bearing features both universal and unique to life) that may avoid some of the problems inherent in fulfillment of the aforementioned constraints. Specifically, the Switzer laboratory is examining ANAs with novel changes to (i) base-pairing domains, (ii) backbone charges and (iii) the sugar. These studies will help to define chemical parameters for molecular evolution. Moreover, our work addresses whether nucleic acid-like molecules are sufficient to enable the origin of life and what limitations exist for life elsewhere in the universe based on a single biopolymer (eg. RNA) rather than multiple biopolymers (DNA, RNA, proteins, carbohydrates). Accomplishments by our group for the past year include: (i) the discovery of surprising fidelity during non-enzymatic transcription of an unnatural base-pair, (ii) the discovery that DNA recombination is possible with artificial Watson-Crick base-pairs, (iii) an assessment of how tethered cations affect DNA topology, and (iv) the discovery that a DNA analogue bearing a simple acyclic sugar replacement of glycerol in place of ribose can support template-directed synthetic reactions.

    Christopher Switzer
    Project Investigator

    Azizul Haque

    Subbarao Nallagatal

    Surajit Sinha

    John Chaput
    Doctoral Student

    Paul Kim
    Doctoral Student

    Dong-Kye Lee
    Doctoral Student

    Objective 1.0
    Determine whether the atmosphere of the early Earth, hydrothermal systems or exogenous matter were significant sources of organic matter.

    Objective 2.0
    Develop and test plausible pathways by which ancient counterparts of membrane systems, proteins and nucleic acids were synthesized from simpler precursors and assembled into protocells.

    Objective 3.0
    Replicating, catalytic systems capable of evolution, and construct laboratory models of metabolism in primitive living systems.

    Objective 9.0
    Determine the presence of life's chemical precursors and potential habitats for life in the outer solar system.