Metals promote sequences of the reverse Krebs cycle
Open accessAbstract
The reverse tricarboxylic acid (rTCA) cycle (also known as the reverse Krebs cycle) is a central anabolic biochemical pathway whose origins are proposed to trace back to geochemistry, long before the advent of enzymes, RNA or cells, and whose imprint remains intimately embedded in the structure of core metabolism. If it existed, a primordial version of the rTCA cycle would necessarily have been catalysed by naturally occurring minerals at the earliest stage of the transition from geochemistry to biochemistry. Here, we report non-enzymatic promotion of multiple reactions of the rTCA cycle in consecutive sequence, whereby 6 of its 11 reactions were promoted by Zn 2+, Cr 3+ and Fe 0 in an acidic aqueous solution. Two distinct three-reaction sequences were achieved under a common set of conditions. Selectivity was observed for reduction reactions producing rTCA cycle intermediates compared with those leading off-cycle. Reductive amination of ketoacids to furnish amino acids was observed under similar conditions. The emerging reaction network supports the feasibility of primitive anabolism in an acidic, metal-rich reducing environment.
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There is an important body of work proposing synthetic routes towards di- and tricarboxylic acids, which are core metabolites of the TCA/rTCA cycle.
“In addition to the above approaches, there is an important body of work that proposes synthetic routes towards di- and tricarboxylic acids, which constitute core metabolites of the tricarboxylic acids (TCA/rTCA) cycle, also called the (reductive) Krebs cycle (e in Scheme 1).49,50”
From The protometabolic nature of prebiotic chemistry (2023) · cites this paper as [49]
The rTCA cycle is an appealing candidate for early prebiotic metabolism because, similar to the oxidative TCA cycle, it produces the five universal precursors to biological metabolism.
“The rTCA cycle is an appealing candidate for early prebiotic metabolism because, similar to the oxidative TCA cycle, it produces the five universal precursors to biological metabolism (12, 14, 18).”
From Regulation and function of the mammalian tricarboxylic acid cycle (2023) · cites this paper as [12]
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- Authors
- Muchowska, K. B., Varma, S. J., Chevallot-Beroux, E., Lethuillier-Karl, L., Li, G., & Moran, J.
- Affiliations
- Centre National de la Recherche Scientifique (FR)
- Corresponding author
- Moran, Joseph
- ORCID
- Venue
- Nature Ecology & Evolution
- Published
- 2017-10-02
- Volume
- 1
- Issue
- 11
- Pages
- 1716-1721
- ISSN
- 2397-334X (ISSN-L)
- PMC
- PMC5659384
- OpenAlex
- W2758609433
- Cited by
- 228
- References
- 52
- Citations by year
- 2026: 25 · 2025: 14 · 2024: 22 · 2023: 26 · 2022: 32 · 2021: 30 · 2020: 21 · 2019: 22 · 2018: 31 · 2017: 4
- FWCI
- 11.67
- Type
- journal article
- Language
- en
- Open access
- green
- www.ncbi.nlm.nih.gov
- Licence
- Locations
- Nature Ecology & Evolution (publishedVersion)
- PubMed (publishedVersion)
- PubMed Central (acceptedVersion)
- Funders
- Agence Nationale de la Recherche (ANR-10-LABX-0026)
- Topics
- Physical Sciences › Physics and Astronomy › Astronomy and Astrophysics › Origins and Evolution of Life
- Physical Sciences › Chemistry › Organic Chemistry › Chemical Reaction Mechanisms
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Enzyme Catalysis and Immobilization
- Keywords
- reverse tricarboxylic acid cycle, non-enzymatic catalysis, metal ions, zinc, chromium, iron, origin of metabolism, reductive amination, amino acid synthesis, prebiotic chemistry
- MeSH terms
- Chromium, Citric Acid Cycle, Ions, Iron, Zinc, Evolution, Chemical
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