The metabolic processes of life have a close relationship with inorganic chemistry: to obtain the metabolic path that gives them the components with which they were built, the first organisms replaced with their own enzymes the metals that catalyzed a prebiotic chain of reactions very similar to the biological fixation of carbon dioxide (its conversion into organic compounds); This, then, would follow the footsteps of that precursor prior to the appearance of life. Or, at least, this seems to be the conclusion that follows from the experiments of Sreejith J. Varma and his collaborators, of the University of Strasbourg. As this group explains in a pre-publication that appeared in the bioRxiv repository, it seems that the oldest metabolic system had an immediate prebiotic predecessor:
Varma and his team found that various powdered metals reacted in a saline solution with carbon dioxide. They determined that in a wide range of reaction conditions, acetate and pyruvate were formed in this way; it was, therefore, the same route (chain of reactions that leads from one substance to another) by which many bacteria and archaea fix the carbon dioxide in the air. Of this route, in addition, it is possible to suppose that it already acted in the last common ancestor to all the present organisms. The interpretation of the result is that life could have arisen, without intermediate gaps, from the chemistry of the primitive Earth.
The first life forms would have appropriated a chain of chemical reactions that saved the energy jump between the reducing metals of the earth’s crust and the oxidizing atmosphere, writes the group of researchers. Carbon dioxide binds to the surface of metals and takes electrons. The water dissociates and acetate, pyruvate and other small organic molecules form (the team of researchers has also found part of a second biochemical process of fixation of carbon dioxide, the inverse reductive cycle of Krebs, in these prebiotic metallic reactions).
For the rest, the research has only shown up to now the formation of the precursors of the biomolecules. The details of the process, especially the supposed similarity with the route of acetyl coenzyme A, have not yet been accredited.
Source: investigacionyciencia.es
