![Distribution and protein structures of ancestral energy conservation enzymes in bacteria and archaea. For escape as free-living cells, metabolism had to achieve the state of a balanced stoichiometric reaction145, called redox balance in physiology, and the exergonic reactions of electron transfer from H2 to CO2 needed to be coupled to the pumping of ions from the inside of the cell to the outside (chemiosmotic coupling), as in modern cells. Prior to the coupling of CO2 reduction to ion pumping, the natural pH gradient provided by serpentinizing systems (pH 9–11, vs. sea water (pH 6.5146) was harnessable with the help of simple, abiotically synthesized hydrophobics147,148 such as fatty acids, which were recently shown to support the ATP-synthesizing function of a rotor-stator ATPase149. -- [q-bio.PE]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/Intermediate.png?fit=1200%2C678&ssl=1)
[q-bio.PE] The origin of life required the emergence of metabolism, an autocatalytic network of enzymatic reactions that synthesize amino acids, nucleotides and cofactors.
At the origin of metabolism there were no enzymes–how did it start? Empirical studies addressing early metabolic evolution are lacking. Harnessing protein structures for metabolic enzymes, we identify intermediate states in primordial metabolic assembly.
We show that enzymatic metabolism in the universal common ancestor was incomplete, undergoing final assembly independently in the lineages leading to Bacteria and Archaea. Native transition metals–Fe0, Co0, Ni0, Pd0–served as the catalytic forerunners of both enzymes and cofactors at metabolic origin while phosphite supplied energy, as it phosphorylates AMP to ADP and serine to phosphoserine using native metal catalysts in water.
Phosphite and native metals occur in serpentinizing hydrothermal systems, identifying an energy-supplying, catalytic site of metabolic origin. Cofactors liberated nascent metabolism from native metal catalysts, engendering its autocatalytic state.
Natalia Mrnjavac, Nadja K. Hoffmann, Manon L. Schlikker, Maximilian Burmeister, Loraine Schwander, Carolina Garcia Garcia, Max Brabender, Mike Steel, Daniel H. Huson, Sabine Metzger, Quentin Dherbassy, Bernhard Schink, Mirko Basen, Joseph Moran, Harun Tueysuez, Martina Preiner, William F. Martin
Comments: 70 pages, 14 figures
Subjects: Populations and Evolution (q-bio.PE)
Cite as: arXiv:2510.08410 [q-bio.PE] (or arXiv:2510.08410v3 [q-bio.PE] for this version)
https://doi.org/10.48550/arXiv.2510.08410
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Submission history
From: Natalia Mrnjavac
[v1] Thu, 9 Oct 2025 16:29:34 UTC (31,745 KB)
[v2] Wed, 6 May 2026 15:59:59 UTC (24,185 KB)
[v3] Thu, 7 May 2026 08:10:11 UTC (19,672 KB)
https://arxiv.org/abs/2510.08410
Astrobiology,
