Primitive homochiral polyester formation driven by tartaric acid and calcium availability

• 成果类型: Article
• 署名作者: Chen, Chen; Yi, Ruiqin; Igisu, Motoko; Afrin, Rehana; Sithamparam, Mahendran; Chandru, Kuhan; Ueno, Yuichiro; Sun, Linhao; Laurenzi, Tommaso; Eberini, Ivano; Fraccia, Tommaso P.; Wang, Anna; Cleaves, H. James; Jia, Tony Z.
• 署名单位: Chinese Academy of Sciences; Guangzhou Institute of Geochemistry, CAS; Japan Agency for Marine-Earth Science & Technology (JAMSTEC); Universiti Kebangsaan Malaysia; Universiti Kebangsaan Malaysia; University of Duisburg Essen; Kanazawa University; University of Milan; University of New South Wales Sydney; University of New South Wales Sydney; University of New South Wales Sydney; University of New South Wales Sydney; Howard University
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-12245
• DOI: 10.1073/pnas.2419554122
• 发表日期: 2025-03-25
• 关键词: building-blocks; origin; amino; LIFE; rna; kinetics; MODEL; ocean

摘要

alpha- hydroxy acids (alpha HAs), simple and prebiotically plausible organic monomers, were likely present in various environments on and off Earth and could have played a role in directing the emergence of the first homochiral living systems. Some alpha HAs, which could have been of varying chirality, can undergo dehydration polymerization into polyesters, which could assemble into membraneless microdroplets upon rehydration; understanding these processes is critical for unraveling how simple prebiotic molecules transitioned into more complex systems capable of supporting selective chemical reactions, a key step toward the origin of life. Here, we focused on tartaric acid (TA), a prebiotically relevant alpha HA with multiple chiral forms, to probe plausible mechanisms by which primitive alpha HA and polyester- based systems could have participated in selective homochiral polymer synthesis. Enantiopure solutions of D- TA or l- TA polymerize efficiently via dehydration, while racemic Dl- TA polymerization is inhibited due to stereochemical incompatibility. We found that Ca2+ ions influence this process in two significant ways: 1) regulating TA monomer availability through selective crystallization, removing equal amounts of both enantiomers in racemic proportion and thereby enriching the enantiomeric excess of the remaining nonracemic TA solution; and 2) modulating polymerization by suppressing enantiopure TA polymerization while enabling Dl- TA polymerization. These findings suggest that the differential availability of simple inorganic ions, such as Ca2+, could have indirectly mediated the selection of simple organic chiral monomers and the emergence of homochirality in primitive protocell- forming polymers, offering a pathway from nonliving to living matter in early Earth environments.