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PASCAL Robert
Fonction : Directeur de recherches
Thème de Recherche: exter
robert.pascal
univ-montp2.fr
046714229
Bureau: 0, Etg: 3, Bât: 17 - Site : Faculté des sciences
Domaines de Recherche: - Chimie/Chimie organique
- Chimie/Chimie analytique
- Physique
- Chimie
- Planète et Univers/Astrophysique/Astrophysique stellaire et solaire
- Physique/Astrophysique/Astrophysique stellaire et solaire
- Chimie/ou physique
- Sciences du Vivant/Autre
- Planète et Univers/Astrophysique/Planétologie et astrophysique de la terre
- Physique/Astrophysique/Planétologie et astrophysique de la terre
- Chimie/Polymères
- Chimie/Chemo-informatique
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Dernieres productions scientifiques :
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A reassessment of prebiotically relevant chemical agents for the activation of α-amino acids and peptides
Auteur(s): Ajram G., Rossi J.-C., Boiteau L., Pascal R.
(Article) Publié:
Journal Of Systems Chemistry, vol. 7 p.19-28 (2019)
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A reassessment of prebiotically relevant chemical agents for the activation of α-amino acids and peptides
Auteur(s): Ajram G., Rossi J.-C., Boiteau L., Pascal R.
(Article) Publié:
Journal Of Systems Chemistry, vol. 7 p.19-28 (2019)
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5(4H)-Oxazolones as Effective Aminoacylation Reagents for the 3 `-Terminus of RNA
Auteur(s): Liu Z., Hanson Cassandra, Ajram G., Boiteau L., Rossi J.-C., Danger G., Pascal R.
(Article) Publié:
Synlett, vol. 28 p.73-77 (2017)
DOI: 10.1055/s-0036-1588647
Résumé: Nucleosides and methylated nucleotide models were used as substrates to identify pathways for the chemical aminoacylation of ribonucleic acids (RNA) as a prerequisite for the evolution of translation. A selective and comparatively efficient reaction of a 5(4H)-oxazolone with the 2'- and 3'-OH of the ribonucleotide models was observed. Surprisingly, a similar reaction starting from an alpha-amino acid N-carboxyanhydride (NCA), selected as an acylating agent potentially leading to the unprotected ester required for translation, was not observed, which was confirmed using an acylated NCA equivalent. The reasons for this difference are analysed.
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The Prebiotic C-Terminal Elongation of Peptides Can Be Initiated by N-Carbamoyl Amino Acids
Auteur(s): Abou Mrad Ninette, Ajram G., Rossi J.-C., Boiteau L., Duvernay Fabrice, Pascal R., Danger G.
(Article) Publié:
Chemistry - A European Journal, vol. 23 p.7418-7421 (2017)
Ref HAL: hal-01795673_v1
DOI: 10.1002/chem.201700702
Résumé: The formation of peptides upon 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)-promoted activation of N-carbamoylamino acids (CAA), was considered in the scope of our recent works on carbodiimide promoted C-terminus elongation of peptides in a prebiotic context. Thus EDC promoted activation of CAA derivatives of Tyr(Me) or Ala in dilute aqueous medium pH 5.5-6.5 in the presence of excess of AA, resulted in peptide formation by C-terminus activation/elongation. Kinetic results similar to those of EDC-mediated activation of N-acyl-AA lead us to postulate the formation of a 2-amino-5(4H)-oxazolone intermediate by cyclization of the activated CAA, in spite of the absence of epimerization occurred at CAA residues. Thus, in a prebiotic context, CAA may have played a similar role as N-acyl-AA in the initiation of C-terminus peptide elongation.
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Systems chemistry of alpha-amino acids and peptides
Auteur(s): Danger G., Boiteau L., Rossi J.-C., Pascal R.
Chapître d'ouvrage: Systems Chemistry Of Alpha-Amino Acids And Peptides, vol. 2 p.04001 (2014)
Ref HAL: hal-01457936_v1
Résumé: Pathways have been disclosed in the past decade, which support the possibility that alpha-amino acids could have contributed to self-organization processes leading to the emergence of life. It is proposed that the systems chemistry of these simple building blocks may have led to features of self-organization through the realization of protometabolisms based on unidirectional loops involving both peptide formation and breakdown and additional feedback processes. Potential peptide activating agents have been identified. Scenarios of peptide elongation are proposed to account for peptide elongation both at the N-terminus and the C-terminus and new indications that these processes could be involved in symmetry breaking have been provided.
Commentaires: WOS:000342571200019
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