Energetic processes driving potential peptide protometabolisms at the origin of living systems

Abstract : The thesis addresses several issues in prebiotic chemistry in the context of the origins of life through a systems chemistry approach. The first part is devoted to the study of chemical activation processes that are not only important in the formation of polymers, but also to feed the system with energy in order that a far from equilibrium state is maintained, a prerequisite for self-organization. It has been suggested that 5(4H)-oxazolones intermediates formed by C-terminus peptide activation could be involved in self-organization of life. To this aim, we have checked the reactivity of relevant prebiotic reagents previously proposed to activate α-amino acids. None of them led to a satisfactory C-terminus activation of peptides, showing that no general process for feeding a protometabolism of peptides with energy is identified yet, with the notable exception of N-carboxyanhydrides (NCAs) that can be formed through prebiotically relevant pathways. Additionally, we demonstrated that carbodiimides reagents are as efficient in the activation of N-carbamoyl amino acids as in that of the C-terminus of peptides in diluted aqueous media. The second part of the dissertation discloses new results in support of a process of coevolution of peptides and nucleotides. Firstly, a study of non-enzymatic aminoacylation reagents of the 3’-terminus of RNA is presented. Secondly, we assessed co-polymers of α-amino acids and nucleotides bound by phosphoramidate and ester linkages as potential players in chemical evolution. The kinetic relevance of these structures was demonstrated as well as potential chemical processes that allow their formation.
Document type :
Theses
Complete list of metadatas

Cited literature [373 references]  Display  Hide  Download

https://tel.archives-ouvertes.fr/tel-02181480
Contributor : Abes Star <>
Submitted on : Friday, July 12, 2019 - 10:21:06 AM
Last modification on : Saturday, July 13, 2019 - 1:20:24 AM

File

AJRAM_2018_archivage.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-02181480, version 1

Collections

Citation

Ghinwa Ajram. Energetic processes driving potential peptide protometabolisms at the origin of living systems. Other. Université Montpellier, 2018. English. ⟨NNT : 2018MONTS119⟩. ⟨tel-02181480⟩

Share

Metrics

Record views

96

Files downloads

35