Raphaël Plasson

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In this work, we introduce a prebiotically relevant protometabolic pattern corresponding to an engine of deracemization by using an external energy source. The spontaneous formation of a nonracemic mixture of chiral compounds can be observed in out-of-equilibrium systems via a symmetry-breaking phenomenon. This observation is possible thanks to chirally(More)
α-Amino acids are easily accessible through abiotic processes and were likely present before the emergence of life. However, the role they could have played in the process remains uncertain. Chemical pathways that could have brought about features of self-organization in a peptide world are considered in this review and discussed in relation with their(More)
We propose a scenario for the dynamic co-evolution of peptides and energy on the primitive Earth. From a multi component system consisting of hydrogen cyanide, several carbonyl compounds, ammonia, alkyl amine, carbonic anhydride, borate and isocyanic acid, we show that the reversibility of this system leads to several intermediate nitriles, that(More)
The APED model (activation-polymerization-epimerization-depolymerization) is a unique example of a chemical system that allows symmetry breaking through a dynamic process involving indirect network autocatalysis. In its simplest version, the autocatalytic behavior of this model partly relies on the reproduction of local chiral centers in dipeptides through(More)
Since the model proposed by Frank (Frank FC, Biochem Biophys Acta 1953;11:459-463), several alternative models have been developed to explain how an asymmetric non-racemic steady state can be reached by a chirally symmetric chemical reactive system. This paper explains how a stable non-racemic regime can be obtained as a symmetry breaking occurring in a(More)
In this work, pKa values of polyglycines, poly(L-alanines), and poly(L-valines) with a number of residues up to 10 were determined in different conditions of ionic strength (10 and 100 mM) and temperature (from 15 to 60 degrees C) by capillary electrophoresis. For each peptide family, the pKa values were modeled as a function of the number of residues, the(More)
This work deals with the modeling of electrophoretic mobilities of end-charged homopolypeptides. The ionic mobilities of six families of homopolypeptides (polyglycines, poly-L-alanines, poly-L-valines, poly-L-leucines, poly-L-isoleucines, and poly-L-phenylalanines), with polymerization degrees up to 11, have been carefully determined. The electrophoretic(More)
Understanding how biological homochirality emerged remains a challenge for the researchers interested in the origin of life. During the last decades, stable nonracemic steady states of nonequilibrium chemical systems have been discussed as a possible response to this problem. In line with this framework, a description of recycled systems was provided in(More)
The question of the onset of the homochirality on prebiotic Earth still remains a fundamental question in the quest for the origin of life. Recent works in this field introduce the concept of recycling, rather than the traditional open-flow system described by Frank. This approach has been criticized by Blackmond et al. They claimed that such systems are(More)