Description du projet
Une approche physiologique et chimique pour identifier les premières formes de vie sur Terre
L’origine de la vie sur Terre reste un grand mystère. La vie est une réaction chimique. Mais comment, où et de quoi est née la réaction chimique de la vie? Comment s’est déroulée la diversification primordiale du métabolisme? Le projet EcolMetabOrigin, financé par le CER, cherchera à répondre à ces questions en s’appuyant sur la chimie métabolique et l’analyse des réactions biochimiques probables. Les partenaires du projet appliqueront les outils de la physiologie comparative, de la thermodynamique et de la génomique comparative dans une étude pionnière sur le processus d’évolution métabolique précoce. Plus précisément, EcolMetabOrigin étudiera les propriétés thermodynamiques des réseaux métaboliques modernes à la recherche d’informations retenues depuis l’origine géochimique du métabolisme microbien, ainsi que sa trajectoire évolutive jusqu’à l’origine, et la diffusion de l’hème et des cytochromes au cours de la diversification microbienne précoce.
Objectif
Life is a chemical reaction. Over 1000 individual reactions are driven in the direction of cell growth by the coupling of biosyntheses to environmentally available exergonic reactions that are harnessed by a handful of enzymes in energy metabolism. How, where, and from what the chemical reaction of life arose, and how the primordial diversification of metabolism proceeded are the topics of this proposal. Evidence for the process of metabolic origin and traces from the very early course of microbial evolution should be preserved in the chemical reactions of metabolism itself. This concept, traditionally germane to thoughts on biochemical evolution, is (almost) self evident: Enzymes do not perform feats of magic, they just accelerate reactions that tend to occur anyway. Biochemical reactions can therefore themselves harbor relics of, or be holdovers from, metabolic origin. Yet not all reactions are equally old, metabolism has evolved — but how? In this proposal, the tools of comparative physiology, thermodynamics, and comparative genomics, will be applied to investigate the process of early metabolic evolution. Three kinds of data stand central to the work: i) thermodynamic properties of reactions that comprise modern metabolic networks, ii) information contained in the ability of H2 in the presence of Ni3Fe and magnetite catalysts to substitute for ferredoxin and enzymes in biochemical reactions, and iii) information about the evolutionary origin and phylogenetic spread of heme and cytochromes as well as the ecophysiological context of cytochrome origin. The proposed work will deliver groundbreaking insights into the chemical environment at the site of biochemical origins, inform about the pre-enzymatic nature of catalysts and reductants at the origin of metabolism, and offer insights into the course of bioenergetic evolution before and after heme as well as the ancestral function of cytochromes in accessing extracellular electron acceptors.
Champ scientifique
Programme(s)
Thème(s)
Régime de financement
ERC-ADG - Advanced GrantInstitution d’accueil
40225 Dusseldorf
Allemagne