Stereoselective reactions on the primordial Earth
Final Report Abstract
The homochirality of biological molecules is a signature of life, and its origin remains an unanswered essential question. The origin of homochirality requires three steps that include: an initial symmetry breaking to generate a small imbalance in chirality; enrichment of one handedness to amplify the initial imbalance; transmission of steric information across different classes of biomolecules. Despite several reports were published in literature in recent years, mechanisms for each step have been demonstrated only to a limited extent. The interaction that occurs among different classes of biomolecules and the coupling of different transformations would provide indications of their plausibility and would help to establish the compatibility of these chemical reactions in a prebiotic scenario. During this research stay, detailed mechanistic investigation identified a D-sugar-mediated formation of L-amino acids through prebiotic plausible Strecker reaction. Isotopic labeling and synthesis of reactive intermediates, among other analytical tools, were employed to gain insights into the reaction mechanism and to determine which components favor single handedness, hence emergence of biological homochirality. Moreover, the study of the interactions between racemic glyceraldehyde, as the fundamental carbohydrate monomer, and enantiopure peptides, led to the identification of a kinetic resolution during the formation of the Amadori rearrangement product. The enantioenrichment of racemic glyceraldehyde was coupled with the prebiotic synthesis of amino acids, the formose reaction for the synthesis of sugars and the carbonyl sulfide-mediated peptide coupling to form a tandem prebiotic cycle which amplifies the enantiomeric excess of these classes of biomolecules. The identification of this prebiotic network will guide the full understanding of interactions across different classes of biomolecules on the primordial Earth and will offer a new perspective in the Origin of Life field.
Publications
- “Asymmetric Amplification in Peptide-Catalyzed Formation of Tetrose Sugars from Nearly Racemic Amino Acids”, J. Syst. Chem. 2020, 8, 63−72
Alexander X. Jones, Lingshan Wen, Luca Legnani, Jason Chen, Donna G. Blackmond
- “Mechanistic Insight Into the Origin of Stereoselectivity in the Ribose-Mediated Strecker Synthesis of Alanine”, J. Am. Chem. Soc. 2021, 143, 7852−7858
Luca Legnani, Andrea Darù, Alexander X. Jones, Donna G. Blackmond
(See online at https://doi.org/10.1021/jacs.1c03552) - “Prebiotic Access to Enantioenriched Glyceraldehyde Controlled by Peptides”, Chem. Sci. 2021, 12, 6350−6354
Jinhan Yu, Alexander X. Jones, Luca Legnani, Donna G. Blackmond
(See online at https://doi.org/10.1039/D1SC01250A)
