Emergence of homochirality in large molecular systems

Gabin Laurent (1, 2) , David Lacoste (2) , Pierre Gaspard (3)

1 Gulliver (UMR 7083)
2 ESPCI Paris - Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris
3 Center for Nonlinear Phenomena and Complex Systems

The selection of a single molecular handedness, or homochirality across all living matter, is a mystery in the origin of life. Frank's seminal model showed in the fifties how chiral symmetry breaking can occur in non-equilibrium chemical networks. However, an important shortcoming in this classic model is that it considers a small number of species, while there is no reason for the prebiotic system, in which homochirality first appeared, to have had such a simple composition. Furthermore, this model does not provide information on what could have been the size of the molecules involved in this homochiral prebiotic system. Here, we show that large molecular systems are likely to undergo a phase transition towards a homochiral state, as a consequence of the fact that they contain a large number of chiral species. Using chemoinformatics tools, we quantify how abundant are chiral species in the chemical universe of all possible molecules of a given length. Then, we propose that Frank's model should be extended to include a large number of species, in order to possess the transition towards homochirality as confirmed by numerical simulations. Finally, using random matrix theory, we prove that large non-equilibrium reaction networks possess a generic and robust phase transition towards a homochiral state.

Mots clés: homochirality; origin of life; prebiotic chemistry; random matrices; statistical physics; homochirality

Domaines: Mécanique statistique [cond-mat.stat-mech]

Gabin Laurent, David Lacoste, Pierre Gaspard. Emergence of homochirality in large molecular systems. Proceedings of the National Academy of Sciences of the United States of America, 2021, 118 (3), pp.e2012741118. ⟨10.1073/pnas.2012741118⟩. ⟨hal-03117080⟩