A global scale scenario for prebiotic chemistry: silica-based self- assembled mineral structures and formamide

The pathway from simple abiotically made organic compounds to the molecular bricks of life, as we know it, is unknown. The most efficient geological abiotic route to organic compounds results from the aqueous dissolution of olivine, a reaction known as serpentinization (Sleep, N.H., et al. (2004) Proc. Natl. Acad. Sci. USA 101, 12818–12822). In addition to molecular hydrogen and a reducing environment, serpentinization reactions lead to high-pH alkaline brines that can become easily enriched in silica. Under these chemical conditions, the formation of self-assembled nanocrystalline mineral composites, namely silica/carbonate biomorphs and metal silicate hydrate (MSH) tubular membranes (silica gardens), is unavoidable (Kellermeier, M., et al. In Methods in Enzymology, Research Methods in Biomineralization Science (De Yoreo, J., Ed.) Vol. 532, pp 225–256, Academic Press, Burlington, MA). The osmotically driven membranous structures have remarkable catalytic properties that could be operating in the reducing organic-rich chemical pot in which they form. Among one-carbon compounds, formamide (NH2CHO) has been shown to trigger the formation of complex prebiotic molecules under mineral-driven catalytic conditions (Saladino, R., et al. (2001) Biorganic & Medicinal Chemistry, 9, 1249–1253), proton irradiation (Saladino, R., et al. (2015) Proc. Natl. Acad. Sci. USA, 112, 2746–2755), and laser-induced dielectric breakdown (Ferus, M., et al. (2015) Proc Natl Acad Sci USA, 112, 657–662). Here, we show that MSH membranes are catalysts for the condensation of NH2CHO, yielding prebiotically relevant compounds, including carboxylic acids, amino acids, and nucleobases. Membranes formed by the reaction of alkaline (pH 12) sodium silicate solutions with MgSO4 and Fe2(SO4)3·9H2O show the highest efficiency, while reactions with CuCl2·2H2O, ZnCl2, FeCl2·4H2O, and MnCl2·4H2O showed lower reactivities. The collections of compounds forming inside and outside the tubular membrane are clearly specific, demonstrating that the mineral self-assembled membranes at the same time create space compartmentalization and selective catalysis of the synthesis of relevant compounds. Rather than requiring odd local conditions, the prebiotic organic chemistry scenario for the origin of life appears to be common at a universal scale and, most probably, earlier than ever thought for our planet.European Research Council under the European Union’s Seventh Framework Programme (FP7/2007−2013)/ERC Grant Agreement 340863Peer reviewe

Prebiotic Organic Chemistry of Formamide and the Origin of Life in Planetary Conditions: What We Know and What Is the Future

© 2021 by the authors.The goal of prebiotic chemistry is the depiction of molecular evolution events preceding the emergence of life on Earth or elsewhere in the cosmos. Plausible experimental models require geochemical scenarios and robust chemistry. Today we know that the chemical and physical conditions for life to flourish on Earth were at work much earlier than thought, i.e., earlier than 4.4 billion years ago. In recent years, a geochemical model for the first five hundred million years of the history of our planet has been devised that would work as a cradle for life. Serpentinization processes in the Hadean eon affording self-assembled structures and vesicles provides the link between the catalytic properties of the inorganic environment and the impressive chemical potential of formamide to produce complete panels of organic molecules relevant in pre-genetic and pre-metabolic processes. Based on an interdisciplinary approach, we propose basic transformations connecting geochemistry to the chemistry of formamide, and we hint at the possible extension of this perspective to other worlds.This work is supported by the Italian Space Agency ASI DC-VUM-2017-034 CONTRATTO DI FINANZIAMENTO ASI N. 2019-3-U.0, CUP F86C16000000006 “Vita nello spazio—Origine, presenza, persistenza della vita nello spazio, dalle molecole agli estremofili”. The authors would like to thank the European Research Council under the European Union’s Seventh Framework Program (FP7/2013-2020)/ERC grant agreement no. 340863; the Spanish “Ministerio de Educacion y Ciencia” for the financial support to the project CGL2016-78971-P; the Consejería de Transformación Económica, Industria, Conocimiento y Universidades of Junta de Andalucía for financial support to the project PY18-5008.Peer reviewe

Silica Metal Oxide Vesicles Catalyze Comprehensive Prebiotic Chemistry

It has recently been demonstrated that mineral self-assembled structures catalyzing prebiotic chemical reactions may form in natural waters derived from serpentinization, a geological process widespread in the early stages of Earth-like planets. We have synthesized self-assembled membranes by mixing microdrops of metal solutions with alkaline silicate solutions in the presence of formamide (NHCHO), a single-carbon molecule, at 80 °C. We found that these bilayer membranes, made of amorphous silica and metal oxide/hydroxide nanocrystals, catalyze the condensation of formamide, yielding the four nucleobases of RNA, three amino acids and, several carboxylic acids in a single-pot experiment. Besides manganese, iron and magnesium, two abundant elements in the earliest Earth crust that are key in serpentinization reactions, are enough to produce all these biochemical compounds. These results suggest that the transition from inorganic geochemistry to prebiotic organic chemistry is common on a universal scale and, most probably, occurred earlier than ever thought for our planet.We acknowledge fundingfrom the European Research Council under the Europ ean Union’s Seventh Framework Programme (FP7/2007–2013)/European Research Council grant agreement no. 340863 (Prometheus). Ministerio de Economia y Competitividad is acknowledge for ProjectCGL2016-78971-P,AEI/FEDER. MIUR Ministerodell’Istruzione, dell’Universit/ della Ricerca and Scuola Normale Superiore (Pisa, Italy), project PRIN 2015 STARS in the CAOS:Simulation Tools for Astrochemical Reactivity and Spectroscopy in the Cyberinfrastructu re for Astrochemical Organic Species, cod. 2015F59J3R, is acknowledged. This work was supported by COST Action TD 1308. M.I.P.V.acknowledges financial support from CONACyT (CVU 557501/300081) and VIEP-BUAP