This year’s Nobel Prize in Chemistry recognized discoveries that help explain how homochiral biological molecules could have emerged from an initially racemic environment. This fascinating area of research has also been studied at our institute.

You may be interested in reading a recent review article, “The emergence of biological homochirality”, by Agnieszka Kiliszek and Wojciech Rypniewski.

https://pubmed.ncbi.nlm.nih.gov/37677131/

Our colleagues have also published a research paper in Nucleic Acids Research, entitled “Broken symmetry between RNA enantiomers in a crystal lattice”. In this work, they demonstrate how crystallization can break the racemic balance between RNA oligomers on a macroscopic scale. In crystals known as racemic compounds, the two enentiomers can differ significantly in their molecular conformations and interactions within the crystal lattice. Structural differences can result in different stabilities. Remarkably, no initial imbalance between the enantiomers is required to produce this macroscopic effect.

The figure illustrates the structural asymmetry between enantiomers observed in the crystal structure of RNA oligomers (from Kiliszek et al., Nucleic Acids Research, 2021).

Once a significant imbalance between enantiomers had emerged, how could it have been maintained? One possibility is that the imbalance was preserved by the emergence of primitive life: an organism incorporating an excess of one enantiomer could have helped sustain that imbalance, preventing a return to racemic equilibrium.

A possible scenario in which one biological enantiomer is selected from a racemic mixture and enriched, potentially through crystallization, before  being incorporated into a living organism, which helps maintain the resulting imbalance (from Kiliszek, Rypniewski, Acta Biochimimica Polonica, 2023).

https://academic.oup.com/nar/article/49/21/12535/6295534