Adsorption at ambient T under controlled conditions

D3.1 identification of the most reactive systems (toward condensation reactions) for further in-depth characterization

Two very promising systems have been identified, namely (Glu+Leu)/SiO2 and (Asp+Val)/SiO2. They show high-yield polymerization to linear oligopeptides up to n = 11 upon simple thermal activation to moderate temperatures (120-150°C). It breaks the record of polymer length for preparations in prebiotically realistic conditions. A preliminary report on these systems has been submitted for publication.

D3.2 and M3.2 Understanding of adsorption mechanisms on the systems selected in D3.1

Macroscopic studies, IR and preliminary NMR data indicate that the adsorption mechanisms on silica involve the formation of specific patterns of H-bonds. A Ph. D. thesis (Hagop Abadian) is being devoted to in-depth understanding of these adsorption mechanisms using advanced solid-state NMR methods. Additional information is available for adsorption mechanisms on clays (ion-exchange, except for acidic AAs), Fe oxides, and sulfides.

D3.3 and M3.3 Understanding the mechanisms of catalytic activation of biomolecules through their interaction with surface sites

Advanced Mass Spectrometric (FT-ICR) characterization of the peptides produced by catalytic activation of the amino acids has proved very useful to understand the peptide condensation reaction. Elementary steps involved in the formation of short peptides, and from there of longer ones, can be identified in this way.

A Ph.D. thesis will start in October 2018 with the aim to perfect the analytical methods applied to this problem and make them quantitative. Molecular level understanding of the mechanisms for each step will constitute the following stage in the elucidation of polypeptides formation, and is connected to D3.2.

M3.1 A list of model minerals classified with respect to their efficiency in catalyzing condensation reactions

Among tested materials, condensation reactions are most efficient on silica in terms of overall yield. They often, however, produce the evolutionary “dead end” DKP. Higher yields of oligopeptides are obtained on some Fe oxides, and on CuS (covellite). Swelling clay minerals (nontronite and montmorillonite) are not very efficient, and tend to activate decomposition reactions such as decarboxylation.

In addition to Yuriy Sakhno’s post-doc, the PREBIOM project has contributed financially to the M2 internships of Alice Battistella and Bianca Ribetto (both exchange students from Italy), and to the M1 internships (3 months) of Louis Ter-Ovanessian and Maëlla Bostvironnois (CPE-Lyon).
Closely related, but not funded by PREBIOM, are the Ph.D.s of Mariame Akouche (ended 12.2016, ACAV funding), Hagop Abadian (started 11.2017, grant from doctoral school 397), and Lise Besoin (to start 10.2018, ACAV+ funding).