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Updated: May 21, 2025
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Self-assembling Morphologies Obtained from Helical Polycarbodiimide Copolymers and Their Triazole Derivatives
Published on: February 7, 2017
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Primitive homochiral polyester formation driven by tartaric acid and calcium availability
Chen Chen1, Ruiqin Yi2, Motoko Igisu3
1Earth-Life Science Institute, Institute of Future Science, Institute of Science Tokyo, Meguro-ku, Tokyo 152-8550, Japan.
Summary
Calcium ions (Ca2+) influenced tartaric acid polymerization, a key step in life's origin. This ion-mediated process could have selected chiral monomers, leading to homochiral polymers essential for early life.
Area of Science:
- Astrobiology and Origin of Life Research
- Prebiotic Chemistry and Molecular Evolution
Background:
- Alpha-hydroxy acids (αHAs) are plausible prebiotic monomers for early life.
- Dehydration polymerization of αHAs forms polyesters, crucial for protocell development.
- Homochirality is a fundamental property of life, but its prebiotic origin is debated.
Purpose of the Study:
- Investigate tartaric acid (TA) polymerization mechanisms for homochiral polymer synthesis.
- Explore the role of calcium ions (Ca2+) in TA polymerization and enantiomeric selection.
- Elucidate pathways for the emergence of homochirality in prebiotic systems.
Main Methods:
- Studied dehydration polymerization of enantiopure (d-TA, l-TA) and racemic (dl-TA) tartaric acid.
- Investigated the effect of Ca2+ ions on TA monomer availability via crystallization.
- Analyzed Ca2+ modulation of polymerization kinetics for different TA stereoisomers.
Main Results:
- Enantiopure TA polymerized efficiently, while racemic TA polymerization was inhibited.
- Ca2+ ions selectively crystallized racemic TA, enriching the remaining solution's enantiomeric excess.
- Ca2+ suppressed enantiopure TA polymerization but enabled racemic dl-TA polymerization.
Conclusions:
- Ca2+ ions could have indirectly selected chiral monomers and promoted homochirality.
- Differential ion availability may have driven the emergence of homochiral polymers.
- This provides a potential pathway from nonliving matter to early life on Earth.
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